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Condensed Matter
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This is an Open Access Journal

Open Access journal
ISSN (Online) 2410-3896
Published by MDPI

[84 journals]

Condensed Matter, Vol. 7, Pages 44: Effect of Metallic and Non-Metallic
Additives on the Synthesis of Fullerenes in Thermal Plasma
- Authors: Anna Mária Keszler, Éva Kováts, Eszter Bódis, Zoltán Károly, János Szépvölgyi
  First page: 44
  Abstract: The effect of metallic (Fe, Cu, Co, Ni, Ti) and non-metallic additives (Si, B) on the formation of fullerenes from graphite powders was studied in radiofrequency (RF) thermal plasma. The main component of the synthesized fullerene mixtures was C60, but higher fullerenes (C70, C82, and C84) could be detected as well. Fe and Cu additives increased the fullerene content in the soot. In contrast, the fullerene formation decreased in the presence of Ti, Si, and B as compared to the synthesis without additives. However, Ti and B addition enhanced the formation of higher fullerenes. We provide experimental evidence that decreasing the reactor pressure results in a lower yield of fullerene production, in accordance with thermodynamic calculations and numerical simulations published earlier. In the presence of titanium, a significant quantity of TiC was also formed as a by-product. The fullerene mixture synthesized with boron additives showed higher stability during storage in ambient conditions as compared to other samples.
  Citation: Condensed Matter
  PubDate: 2022-06-30
  DOI: 10.3390/condmat7030044
  Issue No: Vol. 7, No. 3 (2022)
Condensed Matter, Vol. 7, Pages 30: Path-Integral Monte Carlo Worm
Algorithm for Bose Systems with Periodic Boundary Conditions
- Authors: Gabriele Spada, Stefano Giorgini, Sebastiano Pilati
  First page: 30
  Abstract: We provide a detailed description of the path-integral Monte Carlo worm algorithm used to exactly calculate the thermodynamics of Bose systems in the canonical ensemble. The algorithm is fully consistent with periodic boundary conditions, which are applied to simulate homogeneous phases of bulk systems, and it does not require any limitation in the length of the Monte Carlo moves realizing the sampling of the probability distribution function in the space of path configurations. The result is achieved by adopting a representation of the path coordinates where only the initial point of each path is inside the simulation box, the remaining ones being free to span the entire space. Detailed balance can thereby be ensured for any update of the path configurations without the ambiguity of the selection of the periodic image of the particles involved. We benchmark the algorithm using the non-interacting Bose gas model for which exact results for the partition function at finite number of particles can be derived. Convergence issues and the approach to the thermodynamic limit are also addressed for interacting systems of hard spheres in the regime of high density.
  Citation: Condensed Matter
  PubDate: 2022-03-29
  DOI: 10.3390/condmat7020030
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 31: Euclidean Q-Balls of Fluctuating
SDW/CDW in the ‘Nested’ Hubbard Model of High-Tc
Superconductors as the Origin of Pseudogap and Superconducting Behaviors
- Authors: Sergei Mukhin
  First page: 31
  Abstract: The origin of the pseudogap and superconducting behaviors in high-Tc superconductors is proposed, based on the picture of Euclidean Q-balls formation that carry Cooper/local-pair condensates inside their volumes. Euclidean Q-balls that describe bubbles of collective spin-/charge density fluctuations (SDW/CDW) oscillating in Matsubara time are found as a new self-consistent solution of the Eliashberg equations in the ‘nested’ repulsive Hubbard model of high-Tc superconductors. The Q-balls arise due to global invariance of the effective theory under the phase rotation of the Fourier amplitudes of SDW/CDW fluctuations, leading to conservation of the ‘Noether charge’ Q in Matsubara time. Due to self-consistently arising local minimum of their potential energy at finite amplitude of the density fluctuations, the Q-balls provide greater binding energy of fermions into local/Cooper pairs relative to the usual Frohlich mechanism of exchange with infinitesimal lattice/charge/spin quasiparticles. We show that around some temperature T* the Q-balls arise with a finite density of superconducting condensate inside them. The Q-balls expand their sizes to infinity at superconducting transition temperature Tc. The fermionic spectral gap inside the Q-balls arises in the vicinity of the ‘nested’ regions of the bare Fermi surface. Solutions are found analytically from the Eliashberg equations with the ‘nesting’ wave vectors connecting ‘hot spots’ in the Brillouin zone. The experimental ‘Uemura plot’ of the linear dependence of Tc on superconducting density ns in high-Tc superconducting compounds follows naturally from the proposed theory.
  Citation: Condensed Matter
  PubDate: 2022-03-31
  DOI: 10.3390/condmat7020031
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 32: Mixtures of Dipolar Gases in Two
Dimensions: A Quantum Monte Carlo Study
- Authors: Sergi Pradas, Jordi Boronat
  First page: 32
  Abstract: We studied the miscibility of two dipolar quantum gases in the limit of zero temperature. The system under study is composed of a mixture of two Bose gases with dominant dipolar interaction in a two-dimensional harmonic confinement. The dipolar moments are all considered to be perpendicular to the plane, turning the dipolar potential in a purely repulsive and isotropic model. Our analysis is carried out by using the diffusion Monte Carlo method, which allows for an exact solution to the many-body problem within some statistical noise. Our results show that the miscibility between the two species is rather constrained as a function of the relative dipolar moments and masses of the two components. A narrow regime is predicted where both species mix and we introduce an adimensional parameter whose value quite accurately predicts the miscibility of the two dipolar gases.
  Citation: Condensed Matter
  PubDate: 2022-04-01
  DOI: 10.3390/condmat7020032
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 33: Superconductivity in the α-Form
Layer Structured Metal Nitride Halide
- Authors: Masashi Tanaka, Noriyuki Kataoka, Takayoshi Yokoya
  First page: 33
  Abstract: Layered metal nitride halides MNX (M = Ti, Zr, Hf; X = Cl, Br, I) have two polymorphs, including α- and β-forms, which have the FeOCl and SmSI structures, respectively. These compounds are band insulators and become metals and show superconductivity after electron doping by intercalating alkali metals between the layers. The superconductivity of β-form had been extensively characterized from decades ago, but it is not easy to consistently interpret all experimental results using conventional phonon-mediated Bardeen–Cooper–Schriefer mechanisms. The titanium compound TiNCl crystallizes only in the α-form structure. TiNCl also exhibits superconductivity as high as ~16 K after electron doping by intercalating metals and/or organic basis. It is important to compare the superconductivity of different M–N networks. However, α-form compounds are vulnerable to moisture, unlike β-form ones. The intercalation compounds are even more sensitive to humid air. Thus, there are few experimental studies on the superconducting mechanism of α-form, although it has been discussed for exotic Cooper-pairing mechanisms. This short review gathers the recent progress in experimental studies of TiNCl.
  Citation: Condensed Matter
  PubDate: 2022-04-01
  DOI: 10.3390/condmat7020033
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 34: Estimation of the Grüneisen
Parameter of High-Entropy Alloy-Type Functional Materials: The Cases of
REO0.7F0.3BiS2 and MTe
- Authors: Fysol Ibna Abbas, Yuki Nakahira, Aichi Yamashita, Md. Riad Kasem, Miku Yoshida, Yosuke Goto, Akira Miura, Kensei Terashima, Ryo Matsumoto, Yoshihiko Takano, Chikako Moriyoshi, Yoshikazu Mizuguchi
  First page: 34
  Abstract: In functional materials such as thermoelectric materials and superconductors, the interplay between functionality, electronic structure, and phonon characteristics is one of the key factors to improve functionality and to understand the underlying mechanisms. In the first part of this article, we briefly review investigations on lattice anharmonicity in functional materials on the basis of the Grüneisen parameter (γG). We show that γG can be a good index for large lattice anharmonicity and for detecting a change in anharmonicity amplitude in functional materials. Then, we show original results on the estimation of γG for recently developed high-entropy alloy-type (HEA-type) functional materials with a layered structure and a NaCl-type structure. As a common trend for those two systems with two- and three-dimensional structures, we found that γG increased with a slight increase in the configurational entropy of mixing (ΔSmix) and then decreased with increasing ΔSmix in the high-entropy region.
  Citation: Condensed Matter
  PubDate: 2022-04-18
  DOI: 10.3390/condmat7020034
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 35: Essential Electronic Properties of
Stage-1 Li/Li+-Graphite-Intercalation Compounds for Different
Concentrations
- Authors: Wei-Bang Li, Shih-Yang Lin, Ming-Fa Lin, Kuang-I Lin
  First page: 35
  Abstract: We use first-principles calculations within the density functional theory (DFT) to explore the electronic properties of stage-1 Li- and Li+-graphite-intercalation compounds (GIC) for different concentrations of LiCx/Li+Cx, with x = 6, 12, 18, 24, 32 and 36. The essential properties, e.g., geometric structures, band structures and spatial charge distributions are determined by the hybridization of the orbitals, the main focus of our work. The band structures/density of states/spatial charge distributions display that Li-GIC shows a blue shift of Fermi energy just like metals, but Li+-GIC still remains as in the original graphite or exhibits so-called semi-metallic properties, possessing the same densities of free electrons and holes. According to these properties, we find that there exist weak but significant van der Waals interactions between interlayers of graphite, and 2s-2pz hybridization between Li and C. There scarcely exist strong interactions between Li+-C. The dominant interaction between the Li and C is 2s-2pz orbital-orbital coupling; the orbital-orbital coupling is not significant in the Li+ and C cases, but dipole-diploe coupling is.
  Citation: Condensed Matter
  PubDate: 2022-05-05
  DOI: 10.3390/condmat7020035
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 36: The Evolution of Geometric Structures,
Electronic Properties, and Chemical Bonding of Small Phosphorus-Boron
Clusters
- Authors: Limei Wen, Qingshan Li, Bingyi Song, Liming Yang, Eric Ganz
  First page: 36
  Abstract: We report a comprehensive theoretical investigation on phosphorus–boron mixed neutral, anionic, and cationic clusters P2Bn/P2Bn−/P2Bn+ (n = 3–7) with two phosphorus atoms and three to seven boron atoms. We reveal the common character of all the structures (i.e., the phosphorus atoms choose to occupy the peripheral position), whereas the boron atoms tend to be in the central and inside position of the ground state phosphorus—boron mixed clusters at each stoichiometry. Any three atoms preferentially form a stable triangle and grow with zigzag shape in a planar network. Interestingly, a series of planar motifs (including tetra-, penta-, and hexa-coordination) have been discovered in the phosphorus–boron clusters. The large binding energies (3.6 to 4.6 eV/atom) and quite large HOMO–LUMO gaps (5 to 10 eV) indicate the high stability of the clusters. The energy differences Δ1E, Δ2E, and energy gaps display oscillating behavior with increasing numbers of boron atoms. The electron affinity (EA) and ionization potential (IP) generally have small variations, with the EA values ranging from 2 to 3 eV, and the IP values ranging from 7 to 9 eV. Chemical bond analysis shows that the existence of multi-center delocalized bonds stabilize the clusters.
  Citation: Condensed Matter
  PubDate: 2022-05-14
  DOI: 10.3390/condmat7020036
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 37: Characterization of Some Physical and
Photocatalytic Properties of CuO Nanofilms Synthesized by a Gentle
Chemical Technique
- Authors: Soumia Aroussi, Mohamed Amine Dahamni, Mostefa Ghamnia, Didier Tonneau, Carole Fauquet
  First page: 37
  Abstract: Pure and Li-doped CuO nanofilms were synthesized on heated glass substrates using the spray-pyrolysis technique. The deposited pure CuO nanofilms were achieved at a precursor molarity of 0.2 M using a solution prepared from copper nitrate trihydrate (Cu(NO3)2·3H2O). Doped Li–CuO nanofilms were obtained using several doping concentrations (3, 6, 9, 12 and 15%) by adding a solution prepared from lithium nitrate (LiNO3). The pure and Li–CuO samples were investigated by different techniques. XRD revealed three dominant peaks (-111), (111) and (211), which are the properties of monoclinic CuO. The increase in Li-doping concentration showed the appearance of other peaks of low intensities detected at 2θ ranging from 49 to 68°. AFM images showed a textured and inhomogeneous surface composed of spherical grains whose size decreased with increasing Li doping. UV–visible spectroscopy showed that the CuO samples were of low transparency; the transmittance was less than 50%. The band-gap energy determined from Tauc’s equation plot increased from 2.157 to 3.728 eV with the increase in Li doping. These values correspond well to the band gap of semiconducting CuO. The photocatalytic properties were accelerated by Li doping, as revealed by the discoloration of aqueous methylene-blue (MB) solution under ultraviolet irradiation.
  Citation: Condensed Matter
  PubDate: 2022-05-25
  DOI: 10.3390/condmat7020037
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 38: Neural Annealing and Visualization of
Autoregressive Neural Networks in the Newman–Moore Model
- Authors: Estelle M. Inack, Stewart Morawetz, Roger G. Melko
  First page: 38
  Abstract: Artificial neural networks have been widely adopted as ansatzes to study classical and quantum systems. However, for some notably hard systems, such as those exhibiting glassiness and frustration, they have mainly achieved unsatisfactory results, despite their representational power and entanglement content, thus suggesting a potential conservation of computational complexity in the learning process. We explore this possibility by implementing the neural annealing method with autoregressive neural networks on a model that exhibits glassy and fractal dynamics: the two-dimensional Newman–Moore model on a triangular lattice. We find that the annealing dynamics is globally unstable because of highly chaotic loss landscapes. Furthermore, even when the correct ground-state energy is found, the neural network generally cannot find degenerate ground-state configurations due to mode collapse. These findings indicate that the glassy dynamics exhibited by the Newman–Moore model caused by the presence of fracton excitations in the configurational space likely manifests itself through trainability issues and mode collapse in the optimization landscape.
  Citation: Condensed Matter
  PubDate: 2022-05-27
  DOI: 10.3390/condmat7020038
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 39: Investigating the Morphology, Optical,
and Thermal Properties of Multiphase-TiO2/MAPbI3 Heterogeneous Thin-Films
for Solar Cell Applications
- Authors: Thembinkosi D. Malevu, Tshwafo E. Motaung, Setumo V. Motloung, Lehlohonolo F. Koao, Teboho P. Mokoena, Motlalepula R. Mhlongo
  First page: 39
  Abstract: The present study evaluates the effect of mesoporous multiphase titanium dioxide (TiO2) nanoparticles (NPs) as an electron transporting layer and investigates the influence of phase composition on the perovskite solar cell (PSC) performances. This study also aims to evaluate PSC performance using conductive silver ink as an alternative counter electrode. The heterogeneous PSC thin-film solar cells were successfully fabricated and assembled by using a simple a doctor blade and two-step spin coating methods under ambient conditions. Scanning electron microscopy (SEM) micrograph images investigate methyl ammonium lead iodide (MAPbI3) crystal formation on the mesoporous TiO2 surface structure. Energy-dispersive x-ray spectroscopy (EDX) spectra reveal excellent qualitative and quantitative analysis corresponding to the SEM images in the TiO2/MAPbI3 heterogeneous thin films. Thermogravimetric analysis (TGA) characterization reveals that the TiO2/MAPbI3 thin films are thermally stable recording a maximum of 15.7% mass loss at 800 °C elevated temperatures. Photoluminescence spectroscopy (PL) characterized the effect of multiphase TiO2 phase transformation on the TiO2/MAPbI3 recombination efficiencies. A maximum of 6% power conversion efficiency (PCE) with the open-circuit voltage (Voc) of 0.58 ± 0.02 V and short circuit current (Jsc) of 3.89 ± 0.17 mAcm−2 was achieved for devices with an active area of 3 × 10−4 m2 demonstrating that the synthesized multiphase TiO2 nanoparticles are promising for large surface area manufacturing. Therefore, it is apparent that multiphase TiO2 NPs play a significant role in the performance of the final device.
  Citation: Condensed Matter
  PubDate: 2022-06-06
  DOI: 10.3390/condmat7020039
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 40: Evolution of the Chern Gap in Kagome
Magnet HoMn6Sn6−xGex
- Authors: Christopher Sims
  First page: 40
  Abstract: The Chern gap is a unique topological feature that can host non-abelian particles. The Kagome lattice hosts Chern fermions. Upon the inclusion of magnetism, the Kagome system hosts a Chern gap at the K points in the lattice. In this work, the effect of Ge doping on HoMn6Sn6 is investigated. It is seen that with increased doping, a multi-stack Chern gap in formed in HoMn6Sn6−xGex. In addition, the Chern gaps are much more pronounced and disperse more in energy in HoMn6Ge6 then in HoMn6Sn6.
  Citation: Condensed Matter
  PubDate: 2022-06-09
  DOI: 10.3390/condmat7020040
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 41: Possible Benefits from
Phonon/Spin-Wave Induced Gaps below or above EF for Superconductivity in
High-TC Cuprates
- Authors: Thomas Jarlborg
  First page: 41
  Abstract: A phonon of appropriate momentum kF will open a band gap at the Fermi energy EF. The gap within the electronic density-of-states (DOS), N(EF), leads to a gain in electronic energy and a loss of elastic energy because of the gap-generating phonon. A BCS-like simulation shows that the energy gain is larger than the loss for temperatures below a certain transition temperature, TC. Here, it is shown that the energy count can be almost as favorable for gaps a little below or above EF. Such gaps can be generated by auxiliary phonons (or even spin- and charge-density waves) with k-vectors slightly different from kF. Gaps not too far from EF will add to the energy gain at the superconducting transition. In addition, a DOS-peak can appear at EF and thereby increase N(EF) and TC. A dip in the DOS below EF will result for temperatures below TC, which is similar to what often is observed in cuprate superconductors. The roles of spin waves and thermal disorders are discussed.
  Citation: Condensed Matter
  PubDate: 2022-06-11
  DOI: 10.3390/condmat7020041
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 42: Properties of Composite Powder Based
on Boron Nitride Prepared under Concentrated Light
- Authors: Lina Sartinska, Anatoliy Kasumov, Alexander Koval, Gennadiy Frolov
  First page: 42
  Abstract: The results of direct synthesis of composite powder based on boron nitride (BN) are considered. Concentrated light heating of the initial boron powder was carried out in a xenon high-flux optical furnace in a nitrogen flow. Formation of particles of the desired sizes and architecture highly dependent of the synthesis conditions. The flow of nitrogen separates the particles depending on their architecture and size. An increase in the distance from the reaction zone leads to the formation of powder with a wider bandgap, increases the amount of amorphous phase, and decreases the amount of oxide in the collected composite powder. However, the close distance to the reaction zone and high temperatures provide a denser packing of the structure on the particle surface and the disappearance of the BN transition phases. Incorporation of the nickel sulfate hexahydrate to initial boron contributes to the formation of graphene-like structures.
  Citation: Condensed Matter
  PubDate: 2022-06-11
  DOI: 10.3390/condmat7020042
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 43: High Precision X-ray Measurements 2021
- Authors: Alessandro Scordo
  First page: 43
  Abstract: High Precision X-ray Measurements 2021 is a Special Issue related to the HPXM2021 conference, held at the INFN Laboratories of Frascati in 2021 [...]
  Citation: Condensed Matter
  PubDate: 2022-06-11
  DOI: 10.3390/condmat7020043
  Issue No: Vol. 7, No. 2 (2022)
Condensed Matter, Vol. 7, Pages 6: Electrode Materials for Supercapacitors
in Hybrid Electric Vehicles: Challenges and Current Progress
- Authors: Sivakumar Rajagopal, Rameez Pulapparambil Vallikkattil, M. Mohamed Ibrahim, Dimiter Georgiev Velev
  First page: 6
  Abstract: For hybrid electric vehicles, supercapacitors are an attractive technology which, when used in conjunction with the batteries as a hybrid system, could solve the shortcomings of the battery. Supercapacitors would allow hybrid electric vehicles to achieve high efficiency and better power control. Supercapacitors possess very good power density. Besides this, their charge-discharge cycling stability and comparatively reasonable cost make them an incredible energy-storing device. The manufacturing strategy and the major parts like electrodes, current collector, binder, separator, and electrolyte define the performance of a supercapacitor. Among these, electrode materials play an important role when it comes to the performance of supercapacitors. They resolve the charge storage in the device and thus decide the capacitance. Porous carbon, conductive polymers, metal hydroxide, and metal oxides, which are some of the usual materials used for the electrodes in the supercapacitors, have some limits when it comes to energy density and stability. Major research in supercapacitors has focused on the design of stable, highly efficient electrodes with low cost. In this review, the most recent electrode materials used in supercapacitors are discussed. The challenges, current progress, and future development of supercapacitors are discussed as well. This study clearly shows that the performance of supercapacitors has increased considerably over the years and this has made them a promising alternative in the energy sector.
  Citation: Condensed Matter
  PubDate: 2022-01-06
  DOI: 10.3390/condmat7010006
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 7: Tin Whisker Growth Suppression Using
NiO Sublayers Fabricated by Dip Coating
- Authors: Jacob D. Buchanan, Vamsi Borra, Md Maidul Islam, Daniel G. Georgiev, Srikanth Itapu
  First page: 7
  Abstract: Whiskers are small crystalline growths, which can grow from certain metals or alloys. Reaching up to several millimeters long, whiskers have the potential to cause device failures due to short circuits and contamination by debris. Tin (Sn) is one such metal that is particularly prone to whisker development. Until the 2006 RoHS Initiative, lead (Pb) was added to tin in small amounts (up to 2%) to greatly reduce the growth of whiskers. Since then, however, industry has switched to lead-free tin solders and coatings, and the issue of whisker growth on tin has attracted new interest. A reactive-sputtering-deposited nickel oxide sublayer was shown recently to strongly suppress the growth of whiskers from an overlaying tin layer. This paper reports on using nickel oxide films, obtained by a sol–gel dip coating method, as whisker suppressing sublayers. The proposed method is simple, low-cost, and can easily be scaled up for manufacturing purposes. The properties of the sol–gel deposited nickel oxide film were examined using SEM, EDS, and Raman spectroscopy. Samples containing the nickel oxide sublayer were observed through SEM periodically over several months to examine the surfaces for whisker development, and the results show that such layers can be very effective in suppressing whisker growth.
  Citation: Condensed Matter
  PubDate: 2022-01-06
  DOI: 10.3390/condmat7010007
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 8: Anodic Activity of Hydrated and
Anhydrous Iron (II) Oxalate in Li-Ion Batteries
- Authors: Fatemeh Keshavarz, Marius Kadek, Bernardo Barbiellini, Arun Bansil
  First page: 8
  Abstract: We discuss the applicability of the naturally occurring compound Ferrous Oxalate Dihydrate (FOD) (FeC2O4·2H2O) as an anode material in Li-ion batteries. Using first-principles modeling, we evaluate the electrochemical activity of FOD and demonstrate how its structural water content affects the intercalation reaction and contributes to its performance. We show that both Li0 and Li+ intercalation in FOD yields similar results. Our analysis indicates that fully dehydrated ferrous oxalate is a more promising anodic material with higher electrochemical stability: it carries 20% higher theoretical Li storage capacity and a lower voltage (0.68 V at the PBE/cc-pVDZ level), compared to its hydrated (2.29 V) or partially hydrated (1.43 V) counterparts.
  Citation: Condensed Matter
  PubDate: 2022-01-12
  DOI: 10.3390/condmat7010008
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 9: Weakly-Interacting Bose–Bose
Mixtures from the Functional Renormalisation Group
- Authors: Felipe Isaule, Ivan Morera
  First page: 9
  Abstract: We provide a detailed presentation of the functional renormalisation group (FRG) approach for weakly-interacting Bose–Bose mixtures, including a complete discussion on the RG equations. To test this approach, we examine thermodynamic properties of balanced three-dimensional Bose–Bose gases at zero and finite temperatures and find a good agreement with related works. We also study ground-state energies of repulsive Bose polarons by examining mixtures in the limit of infinite population imbalance. Finally, we discuss future applications of the FRG to novel problems in Bose–Bose mixtures and related systems.
  Citation: Condensed Matter
  PubDate: 2022-01-20
  DOI: 10.3390/condmat7010009
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 10: Superconductivity and the
Jahn–Teller Polaron
- Authors: Annette Bussmann-Holder, Hugo Keller
  First page: 10
  Abstract: In this article, we review the essential properties of high-temperature superconducting cuprates, which are unconventional isotope effects, heterogeneity, and lattice responses. Since their discovery was based on ideas stemming from Jahn–Teller polarons, their special role, together with the Jahn–Teller effect itself, is discussed in greater detail. We conclude that the underlying physics of cuprates cannot stem from purely electronic mechanisms, but that the intricate interaction between lattice and charge is at its origin.
  Citation: Condensed Matter
  PubDate: 2022-01-20
  DOI: 10.3390/condmat7010010
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 11: ARIA—A VUV Beamline for
EuPRAXIA@SPARC_LAB
- Authors: Fabio Villa, Marcello Coreno, Zeinab Ebrahimpour, Luca Giannessi, Augusto Marcelli, Michele Opromolla, Vittoria Petrillo, Francesco Stellato
  First page: 11
  Abstract: EuPRAXIA@SPARC_LAB is a new Free Electron Laser (FEL) facility that is currently under construction at the Laboratori Nazionali di Frascati of the INFN. The electron beam driving the FEL will be delivered by an X-band normal conducting LINAC followed by a plasma wakefield acceleration stage. It will be characterized by a small footprint and will deliver ultra-bright photon pulses for experiments in the water window to the user community. In addition to the soft-X-rays beamline already planned in the project, we propose the installation of a second photon beamline with seeded FEL pulses in the range between 50 and 180 nm. Here, we will present the FEL generation scheme, the layout of the dedicated beamline and the potential applications of the FEL radiation source in this low energy range.
  Citation: Condensed Matter
  PubDate: 2022-01-22
  DOI: 10.3390/condmat7010011
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 12: Comparison of Ferromagnetic Materials:
Past Work, Recent Trends, and Applications
- Authors: Prithivi Rasaili, Nitin Kumar Sharma, Ajaya Bhattarai
  First page: 12
  Abstract: Despite our traditional concept-based understanding of ferromagnetism, an investigation of this phenomenon has revealed several other facts. Ferromagnetism was previously supposed to be exhibited by only a few elements. Subsequently, it was realized that specific elements with d- or f- orbitals demonstrated this phenomenon. When elements without these orbitals exhibited ferromagnetism, intrinsic origin-based and structural defect-based theories were introduced. At present, nonmagnetic oxides, hexaborides of alkaline-earth metals, carbon structures, and nonmetallic non-oxide compounds are gaining significant attention owing to their potential applications in spintronics, electronics, biomedicine, etc. Therefore, herein, previous work, recent trends, and the applications of these materials and studies based on relevant topics, ranging from the traditional understanding of ferromagnetism to the most recent two-element-based systems, are reviewed.
  Citation: Condensed Matter
  PubDate: 2022-01-24
  DOI: 10.3390/condmat7010012
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 13: Toward an Automated-Algebra Framework
for High Orders in the Virial Expansion of Quantum Matter
- Authors: Aleks J. Czejdo, Joaquin E. Drut, Yaqi Hou, Kaitlyn J. Morrell
  First page: 13
  Abstract: The virial expansion provides a non-perturbative view into the thermodynamics of quantum many-body systems in dilute regimes. While powerful, the expansion is challenging as calculating its coefficients at each order n requires analyzing (if not solving) the quantum n-body problem. In this work, we present a comprehensive review of automated algebra methods, which we developed to calculate high-order virial coefficients. The methods are computational but non-stochastic, thus avoiding statistical effects; they are also for the most part analytic, not numerical, and amenable to massively parallel computer architectures. We show formalism and results for coefficients characterizing the thermodynamics (pressure, density, energy, static susceptibilities) of homogeneous and harmonically trapped systems and explain how to generalize them to other observables such as the momentum distribution, Tan contact, and the structure factor.
  Citation: Condensed Matter
  PubDate: 2022-01-24
  DOI: 10.3390/condmat7010013
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 14: Acknowledgment to Reviewers of
Condensed Matter in 2021
- Authors: Condensed Matter Editorial Office Condensed Matter Editorial Office
  First page: 14
  Abstract: Rigorous peer-reviews are the basis of high-quality academic publishing [...]
  Citation: Condensed Matter
  PubDate: 2022-01-25
  DOI: 10.3390/condmat7010014
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 15: Polaron-Depleton Transition in the
Yrast Excitations of a One-Dimensional Bose Gas with a Mobile Impurity
- Authors: Mingrui Yang, Matija Čufar, Elke Pahl, Joachim Brand
  First page: 15
  Abstract: We present exact numerical data for the lowest-energy momentum eigenstates (yrast states) of a repulsive spin impurity in a one-dimensional Bose gas using full configuration interaction quantum Monte Carlo (FCIQMC). As a stochastic extension of exact diagonalization, it is well suited for the study of yrast states of a lattice-renormalized model for a quantum gas. Yrast states carry valuable information about the dynamic properties of slow-moving mobile impurities immersed in a many-body system. Based on the energies and the first and second-order correlation functions of yrast states, we identify different dynamical regimes and the transitions between them: The polaron regime, where the impurity’s motion is affected by the Bose gas through a renormalized effective mass; a regime of a gray soliton that is weakly correlated with a stationary impurity, and the depleton regime, where the impurity occupies a dark or gray soliton. Extracting the depleton effective mass reveals a super heavy regime where the magnitude of the (negative) depleton mass exceeds the mass of the finite Bose gas.
  Citation: Condensed Matter
  PubDate: 2022-01-26
  DOI: 10.3390/condmat7010015
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 16: Benchmarking Plane Waves Quantum
Mechanical Calculations of Iron(II) Tris(2,2′-bipyridine) Complex by
X-ray Absorption Spectroscopy
- Authors: Nico Sanna, Maurizio Benfatto
  First page: 16
  Abstract: In this work, we used, for the first time, a computational Self-Consistent Field procedure based on plane waves to describe the low and high spin conformational states of the complex [Fe(bpy)3]2+. The results obtained in the study of the minimum energy structures of this complex, a prototype of a wide class of compounds called Spin Cross Over, show how the plane wave calculations are in line with the most recent studies based on gaussian basis set functions and, above all, reproduce within acceptable errors the experimental spectra of X-ray absorption near-edge structure spectroscopy (XANES). This preliminary study shows the capabilities of plane wave methods to correctly describe the molecular structures of metal-organic complexes of this type and paves the way for future even complex computational simulations based on the energy gradient, such as Nudge Elastic Band or ab-initio Born-Oppenheimer molecular dynamics.
  Citation: Condensed Matter
  PubDate: 2022-01-27
  DOI: 10.3390/condmat7010016
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 17: Quantum Reservoir Computing for
Speckle Disorder Potentials
- Authors: Pere Mujal
  First page: 17
  Abstract: Quantum reservoir computing is a machine learning approach designed to exploit the dynamics of quantum systems with memory to process information. As an advantage, it presents the possibility to benefit from the quantum resources provided by the reservoir combined with a simple and fast training strategy. In this work, this technique is introduced with a quantum reservoir of spins and it is applied to find the ground state energy of an additional quantum system. The quantum reservoir computer is trained with a linear model to predict the lowest energy of a particle in the presence of different speckle disorder potentials. The performance of the task is analyzed with a focus on the observable quantities extracted from the reservoir and it is shown to be enhanced when two-qubit correlations are employed.
  Citation: Condensed Matter
  PubDate: 2022-01-28
  DOI: 10.3390/condmat7010017
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 18: Mimicking Multiorbital Systems with
SU(N) Atoms: Hund’s Physics and Beyond
- Authors: Andrea Richaud, Matteo Ferraretto, Massimo Capone
  First page: 18
  Abstract: The physics of many interesting correlated materials can be captured by multiorbital Hubbard models, where conduction electrons feature an additional orbital degree of freedom. The multiorbital characteristic is not a mere complication, but it leads to an immensely richer landscape of physical regimes. One of the key features is the interplay between Hubbard repulsion and Hund’s exchange coupling, which has been shown to lead to orbital-selective correlations and to the existence of correlation-resilient metals (usually called Hund’s metals) defying Mott localization. Here, we show that experimentally available platforms of SU(N)-symmetric ultracold atoms can indeed mimic the rich physics disclosed by multiorbital materials, by exploiting the internal degrees of freedom of multicomponent atoms. We discuss in detail the SU(N) version of interaction-resilient Hund’s metal and some other interesting regimes.
  Citation: Condensed Matter
  PubDate: 2022-02-01
  DOI: 10.3390/condmat7010018
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 19: The 1S0 Pairing Gap in Neutron Matter
- Authors: Stefano Gandolfi, Georgios Palkanoglou, Joseph Carlson, Alexandros Gezerlis, Kevin E. Schmidt
  First page: 19
  Abstract: We report ab initio calculations of the S wave pairing gap in neutron matter calculated using realistic nuclear Hamiltonians that include two- and three-body interactions. We use a trial state, properly optimized to capture the essential pairing correlations, from which we extract ground state properties by means of auxiliary field diffusion Monte Carlo simulations. We extrapolate our results to the thermodynamic limit by studying the finite-size effects in the symmetry-restored projected Bardeen-Cooper-Schrieffer (PBCS) theory and compare our results to other ab initio studies done in the past. Our quantum Monte Carlo results for the pairing gap show a modest suppression with respect to the mean-field BCS values. These results can be connected to cold atom experiments, via the unitarity regime where fermionic superfluidity assumes a unified description, and they are important in the prediction of thermal properties and the cooling of neutron stars.
  Citation: Condensed Matter
  PubDate: 2022-02-01
  DOI: 10.3390/condmat7010019
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 20: Microstructural Analysis of Terbium
Doped Zirconia and Its Biological Studies
- Authors: Suganthan Veerachamy, Sivakumar Rajagopal
  First page: 20
  Abstract: Zirconia has its place in the biomedical industry because of its mechanical strength, bio-inertness, and physiochemical properties. Zirconia was synthesized and doped with Terbium (Tb), a lanthanide that was reported to show a photoluminescence property, which was a major characteristic for carcinogenic studies. Zirconia and Tb doped Zirconia were synthesized using the co-precipitation technique and were sintered at a temperature ranging from 900 to 1200 °C. The Zirconia sample and Tb doped Zirconia were thus studied for structural diversities using the X-ray powder diffraction technique (XRD), FTIR, FE-SEM, and TEM. From XRD, Zirconia phase transformation from monoclinic to tetragonal phase was observed, which signified limited fracture, elasticity, and crack formation. It was evident that Terbium stabilized the tetragonal phase of Zirconia, which reportedly shows mechanical properties, which include fracture toughness and flexural strength. The particle size of the Zirconia was comparatively more than the Tb doped Zirconia. The particle size of Zirconia ranged between 176 nm and 393 nm and the particle size of Tb doped Zirconia ranged between 110 nm and 343 nm. The biocompatibility of both the samples was tested using an Mg-63 cell line, and the cell viability was observed to be higher in Tb doped Zirconia when compared to the undoped Zirconia sample.
  Citation: Condensed Matter
  PubDate: 2022-02-03
  DOI: 10.3390/condmat7010020
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 21: Planar Cu and O NMR and the Pseudogap
of Cuprate Superconductors
- Authors: Marija Avramovska, Jakob Nachtigal, Stefan Tsankov, Jürgen Haase
  First page: 21
  Abstract: Recently, an analysis of all available planar oxygen shift and relaxation data for the cuprate high-temperature superconductors showed that the data can be understood with a simple spin susceptibility from a metallic density of states common to all cuprates. It carries a doping dependent but temperature independent pseudogap at the Fermi surface, which causes the deviations from normal metallic behavior, also in the specific heat. Here, a more coherent, unbiased assessment of all data, including planar Cu, is presented and consequences are discussed, since the planar Cu data were collected and analyzed prior to the O data. The main finding is that the planar Cu shifts for one direction of the external magnetic field largely follow from the same states and pseudogap. This explains the shift suppression stated more recently, which leads to the failure of the Korringa relation in contrast to an enhancement of the relaxation due to antiferromagnetic spin fluctuations originally proposed. However, there is still the need for a second spin component that appears to be associated with the Cu 3d(x2−y2) hole to explain the complex Cu shift anisotropy and family dependence. Furthermore, it is argued that the planar Cu relaxation which was reported recently to be rather ubiquitous for the cuprates, must be related to this universal density of states and the second spin component, while not being affected by the simple pseudogap. Thus, while this universal metallic density of states with a pseudogap is also found in the planar Cu data, there is still need for a more elaborate scenario that eludes planar O.
  Citation: Condensed Matter
  PubDate: 2022-02-23
  DOI: 10.3390/condmat7010021
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 22: Effect of Borophene and Graphene on
the Elastic Modulus of PEDOT:PSS Film—A Finite Element Study
- Authors: Gbolahan Joseph Adekoya, Oluwasegun Chijioke Adekoya, Emmanuel Rotimi Sadiku, Yskandar Hamam, Suprakas Sinha Ray
  First page: 22
  Abstract: A finite element method (FEM) was employed to investigate the interaction of borophene nanoplatelets (BNPs) and graphene nanoplatelets (GNPs) on the mechanical properties of Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) PEDOT:PSS film. A 3D random distribution of the inclusion into the PEDOT:PSS matrix was constructed by developing a 145 × 145 × 145 representative volume element (RVE) with a 4% volume fraction of BNPs and GNPs. In comparison to the pristine PEDOT:PSS, the calculated effective elastic moduli of the BNP-PEDOT:PSS and GNP-PEDOT:PSS nanocomposites exhibited 9.6% and 10.2% improvement, respectively. The predicted FE results were validated by calculating the elastic moduli of the nanocomposites using a modified Halpine-Tsai (H-T) model. The reinforcing effect of the inclusion into the PEDOT:PSS film offers a promising electrode with improved mechanical stability. Consequently, this intriguing result makes the BNP/PEDOT:PSS nanocomposite highly promising for further investigation and application in cutting-edge devices such as touchscreen, thermoelectric, light-emitting diode, electrochemical, photodiode, sensor, solar cell, and electrostatic devices.
  Citation: Condensed Matter
  PubDate: 2022-02-23
  DOI: 10.3390/condmat7010022
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 23: Plasma-Generated X-ray Pulses:
Betatron Radiation Opportunities at EuPRAXIA@SPARC_LAB
- Authors: Francesco Stellato, Maria Pia Anania, Antonella Balerna, Simone Botticelli, Marcello Coreno, Gemma Costa, Mario Galletti, Massimo Ferrario, Augusto Marcelli, Velia Minicozzi, Silvia Morante, Riccardo Pompili, Giancarlo Rossi, Vladimir Shpakov, Fabio Villa, Alessandro Cianchi
  First page: 23
  Abstract: EuPRAXIA is a leading European project aimed at the development of a dedicated, ground-breaking, ultra-compact accelerator research infrastructure based on novel plasma acceleration concepts and laser technology and on the development of their users’ communities. Within this framework, the Laboratori Nazionali di Frascati (LNF, INFN) will be equipped with a unique combination of an X-band RF LINAC generating high-brightness GeV-range electron beams, a 0.5 PW class laser system and the first fifth-generation free electron laser (FEL) source driven by a plasma-based accelerator, the EuPRAXIA@SPARC_LAB facility. Wiggler-like radiation emitted by electrons accelerated in plasma wakefields gives rise to brilliant, ultra-short X-ray pulses, called betatron radiation. Extensive studies have been performed at the FLAME laser facility at LNF, INFN, where betatron radiation was measured and characterized. The purpose of this paper is to describe the betatron spectrum emitted by particle wakefield acceleration at EuPRAXIA@SPARC_LAB and provide an overview of the foreseen applications of this specific source, thus helping to establish a future user community interested in (possibly coupled) FEL and betatron radiation experiments. In order to provide a quantitative estimate of the expected betatron spectrum and therefore to present suitable applications, we performed simple simulations to determine the spectrum of the betatron radiation emitted at EuPRAXIA@SPARC_LAB. With reference to experiments performed exploiting similar betatron sources, we highlight the opportunities offered by its brilliant femtosecond pulses for ultra-fast X-ray spectroscopy and imaging measurements, but also as an ancillary tool for designing and testing FEL instrumentation and experiments.
  Citation: Condensed Matter
  PubDate: 2022-02-24
  DOI: 10.3390/condmat7010023
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 24: Absence of Spin Frustration in the
Kagomé Layers of Cu2+ Ions in Volborthite Cu3V2O7(OH)2·2H2O
and Observation of the Suppression and Re-Entrance of Specific Heat
Anomalies in Volborthite under an External Magnetic Field
- Authors: Myung-Hwan Whangbo, Hyun-Joo Koo, Eva Brücher, Pascal Puphal, Reinhard K. Kremer
  First page: 24
  Abstract: We determined the spin exchanges between the Cu2+ ions in the kagomé layers of volborthite, Cu3V2O7(OH)2·2H2O, by performing the energy-mapping analysis based on DFT+U calculations, to find that the kagomé layers of Cu2+ ions are hardly spin-frustrated, and the magnetic properties of volborthite below ~75 K should be described by very weakly interacting antiferromagnetic uniform chains made up of effective S = 1/2 pseudospin units. This conclusion was verified by synthesizing single crystals of not only Cu3V2O7(OH)2·2H2O but also its deuterated analogue Cu3V2O7(OD)2·2D2O and then by investigating their magnetic susceptibilities and specific heats. Each kagomé layer consists of intertwined two-leg spin ladders with rungs of linear spin trimers. With the latter acting as S = 1/2 pseudospin units, each two-leg spin ladder behaves as a chain of S = 1/2 pseudospins. Adjacent two-leg spin ladders in each kagomé layer interact very weakly, so it is required that all nearest-neighbor spin exchange paths of every two-leg spin ladder remain antiferromagnetically coupled in all spin ladder arrangements of a kagomé layer. This constraint imposes three sets of entropy spectra with which each kagomé layer can exchange energy with the surrounding on lowering the temperature below ~1.5 K and on raising the external magnetic field B. We discovered that the specific heat anomalies of volborthite observed below ~1.5 K at B = 0 are suppressed by raising the magnetic field B to ~4.2 T, that a new specific heat anomaly occurs when B is increased above ~5.5 T, and that the imposed three sets of entropy spectra are responsible for the field-dependence of the specific heat anomalies.
  Citation: Condensed Matter
  PubDate: 2022-02-28
  DOI: 10.3390/condmat7010024
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 25: Electrical Transport Measurements on
Layered La(O,F)BiS2 under Extremely High Pressure
- Authors: Ryo Matsumoto, Sayaka Yamamoto, Yoshihiro Nemoto, Yuki Nishimiya, Yoshihiko Takano
  First page: 25
  Abstract: Layered La(O,F)BiS2 exhibits drastic enhancements of the superconducting transition temperature (Tc) under high pressure among the BiS2-based superconducting family. However, the high-pressure application beyond a high-Tc phase of the monoclinic structure has not been conducted. In this study, the electrical transport properties in La(O,F)BiS2 single crystal are measured under high pressures up to 83 GPa. An insulating phase without superconductivity is observed under a higher-pressure region above 16 GPa. Moreover, the sample exhibits metallicity and superconductivity above 60 GPa. The newly observed hidden semiconducting phase and reentrant superconductivity have attracted much attention in BiS2-based compounds.
  Citation: Condensed Matter
  PubDate: 2022-03-02
  DOI: 10.3390/condmat7010025
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 26: Topological Phases of an Interacting
Majorana Benalcazar–Bernevig–Hughes Model
- Authors: Alfonso Maiellaro, Fabrizio Illuminati, Roberta Citro
  First page: 26
  Abstract: We study the effects of Coulomb repulsive interactions on a Majorana Benalcazar–Bernevig–Huges (MBBH) model. The MBBH model belongs to the class of second-order topological superconductors (HOTSC2), featuring robust Majorana corner modes. We consider an interacting strip of four chains of length L and perform a density matrix renormalization group (DMRG) numerical simulation based on a tensor-network approach. Study of the non-local fermionic correlations and the degenerate entanglement spectrum indicates that the topological phases are robust in the presence of interactions, even in the strongly interacting regime.
  Citation: Condensed Matter
  PubDate: 2022-03-04
  DOI: 10.3390/condmat7010026
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 27: Antimony (Sb)-Based Anodes for
Lithium–Ion Batteries: Recent Advances
- Authors: Sreejesh Moolayadukkam, Kaveramma Appachettolanda Bopaiah, Priyanka Karathan Parakkandy, Siby Thomas
  First page: 27
  Abstract: To mitigate the use of fossil fuels and maintain a clean and sustainable environment, electrochemical energy storage systems are receiving great deal of attention, especially rechargeable batteries. This is also associated with the growing demand for electric vehicles, which urged the automotive industries to explore the capacities of new materials for use in lithium–ion batteries (LIBs). Graphite is still employed as an anode in large majority of currently available commercial LIBs preserving their better cyclic stability despite enormous research efforts to identify viable alternatives with improved power and energy density. From this point of view, antimony acts as a promising material because it has good theoretical capacity, high volumetric capacity, good reactivity with lithium and good electronic conductivities. Recently, there have been many works that focused on the development of antimony as an alternative anode. This review tries to give a bird’s eye view comprising the experimental and theoretical insights on the developments in the direction of using antimony and antimony composites as anodes for rechargeable Li.
  Citation: Condensed Matter
  PubDate: 2022-03-05
  DOI: 10.3390/condmat7010027
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 28: Study of Light Polarization by
Ferrofluid Film Using Jones Calculus
- Authors: Alberto Tufaile, Michael Snyder, Adriana Pedrosa Biscaia Tufaile
  First page: 28
  Abstract: We studied the polarized light patterns obtained using a thin film of ferrofluid subjected to an applied magnetic field. We obtained patterns of polarized light with magnetic field configurations between parallel plates, monopolar, tetrapolar, and hexapolar, and studied how polarized light varies for different intensities and orientations of the applied magnetic field. Using the Jones calculus, we explored the key optical properties of this system and how these properties relate to the applied magnetic field. We have observed general aspects of polarized light obtained by transmission in a Ferrocell using polariscopes and analyzing the resulting Jones vector, such as the formation and rotation of dark bands known as isogyres. We suggest that in a thin film of ferrofluid as in a Ferrocell, two effects occur. The primary effect is dichroism, which is more sensitive to the component of the magnetic field in the direction parallel to the film plane. The secondary effect is the birefringence that can be observed by analyzing the circular polarization of light. Birefringence is related to the thin film thickness of ferrofluid.
  Citation: Condensed Matter
  PubDate: 2022-03-09
  DOI: 10.3390/condmat7010028
  Issue No: Vol. 7, No. 1 (2022)
Condensed Matter, Vol. 7, Pages 29: The Strange-Metal Behavior of Cuprates
- Authors: Giovanni Mirarchi, Götz Seibold, Carlo Di Castro, Marco Grilli, Sergio Caprara
  First page: 29
  Abstract: Recent resonant X-ray scattering experiments on cuprates allowed to identify a new kind of collective excitations, known as charge density fluctuations, which have finite characteristic wave vector, short correlation length and small characteristic energy. It was then shown that these fluctuations provide a microscopic scattering mechanism that accounts for the anomalous transport properties of cuprates in the so-called strange-metal phase and are a source of anomalies in the specific heat. In this work, we retrace the main steps that led us to attributing a central role to charge density fluctuations in the strange-metal phase of cuprates, discuss the state of the art on the issue and provide an in-depth analysis of the contribution of charge density fluctuations to the specific heat.
  Citation: Condensed Matter
  PubDate: 2022-03-14
  DOI: 10.3390/condmat7010029
  Issue No: Vol. 7, No. 1 (2022)