| Publisher: AIP
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Similar Journals
|
Journal of Applied Physics
Journal Prestige (SJR): 0.739  Citation Impact (citeScore): 2 Number of Followers: 69  Hybrid journal (It can contain Open Access articles)ISSN (Print) 0021-8979 - ISSN (Online) 1089-7550 Published by AIP  [28 journals]
|
- Mn impurity band and the effects of Mn position in III–V lattice:
Pivotal contributions of Władek Walukiewicz to the understanding of
ferromagnetism in semiconductors-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 200901
Abstract: This paper describes the contributions made by Władysław (Władek) Walukiewicz and his colleagues to the field of ferromagnetic semiconductor (FMS) alloys, such as (Ga,Mn)As. We focus on two key accomplishments. First, this team has predicted the formation of Mn interstitials in these materials, which have a profound effect on ferromagnetism in semiconductors. Additionally, identifying the conditions at which interstitials form has provided grounds for optimizing their ferromagnetic properties. Second, by applying the approach of band anticrossing to ferromagnetic semiconductors, this team has mapped out the properties of an Mn-derived impurity band in these materials. This is of particular importance in the field, because holes, which reside in the Mn-derived impurity band, are the very mechanism responsible for ferromagnetic order in FMSs. We discuss the effect that these accomplishments have on our understanding of FMSs and how they have contributed to progress in this area. We then describe the pathways that these achievements have opened up toward further progress in both basic and applied fronts of ferromagnetism in semiconducting systems; and we present our perspective on where additional work along the lines initiated by Władek Walukiewicz should be extended to further benefit this field.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0176698
Issue No: Vol. 134, No. 20 (2023)
-
- Resonant interactions involving local vibrational modes in crystals
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 201101
Abstract: When an impurity with a light mass is inserted into a crystal, it can undergo a high-frequency oscillation referred to as a local vibrational mode (LVM). A Fermi resonance may occur between the LVM and lower-frequency modes of the defect. The LVM may also interact with phonons or the electromagnetic field. Understanding these interactions can help model and control diffusion, defect reactions, and thermal conductivity. LVMs have been probed in semiconductors using pressure and alloying as experimental parameters, resulting in anticrossing between localized and extended vibrational modes. These types of vibrational interactions could play an important role in the stability and thermal properties of organic–inorganic hybrid semiconductors. The coupling between an LVM and electromagnetic wave yields an “LVM polariton,” an excitation that has significant vibrational and electric-field amplitudes.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0177629
Issue No: Vol. 134, No. 20 (2023)
-
- Ultra-efficient machine learning design of nonreciprocal thermal absorber
for arbitrary directional and spectral radiation-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203101
Abstract: Development of nanophotonics has made it possible to control the wavelength and direction of thermal radiation emission, but it is still limited by Kirchhoff's law. Magneto-optical materials or Weyl semimetals have been used in recent studies to break the time-reversal symmetry, resulting in a violation of Kirchhoff's law. Currently, most of the work relies on the traditional optical design basis and can only realize the nonreciprocal thermal radiation at a specific angle or wavelength. In this work, on the basis of material informatics, a design framework of a multilayer nonreciprocal thermal absorber with high absorptivity and low emissivity at any arbitrary wavelength and angle is proposed. Through a comprehensive investigation of the underlying mechanism, it has been discovered that the nonreciprocal thermal radiation effect is primarily attributed to excitation of the cavity mode at the interface between the metal and the multilayer structure. Moreover, the impact of factors, such as layer count, incidence angle, extinction coefficient, and applied magnetic field on nonreciprocal thermal radiation, is thoroughly explored, offering valuable insights to instruct the design process. Additionally, by expanding the optimization objective, it becomes feasible to design fixed dual-band or even multi-band nonreciprocal thermal absorbers. Consequently, this study offers essential guidelines for advancing the control of nonreciprocal thermal radiation.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0177207
Issue No: Vol. 134, No. 20 (2023)
-
- Induction of ice VII structure with secondary shock compression by
backward Raman scattering in plasmas-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203102
Abstract: Forward stimulated Raman scattering and backward stimulated Raman scattering (BSRS) are measured when an intense 532 nm nanosecond pulsed laser is focused into water and heavy water. The investigation reveals a significant observation: the formation of the ice VII structure exclusively occurs in the backward direction when optical breakdown takes place, provided that the input energy falls below 90 mJ for liquid water or 75 mJ for heavy water. This phase transition is attributed to secondary shock compression, which comes from energy transfer and compression between the BSRS in plasmas with the pump laser. The optical breakdown experiment under pre-pressure reveals that the shock compression in the back direction is approximately 2.3 times that of the forward direction. This research is useful for shock compression and dynamics in plasmas.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0176332
Issue No: Vol. 134, No. 20 (2023)
-
- Role of Pauli blocking for enhancement of saturable absorption in MoS 2
/PEDOT:PSS nanocomposite films-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203103
Abstract: We have effectively shown a technique for significantly altering the nonlinear saturable absorption (SA) properties of nanocomposite films (NCFs) based on poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) and molybdenum disulfide (MoS2) by regulating MoS2 concentration and input pulse energy of the laser. The NCFs are made using the straightforward drop-cast process on a glass substrate with varying quantities of MoS2. The produced NCFs’ refractive index (n) and extinction coefficient (k) values are determined using the Kramers–Kronig equations. Nonlinear studies show that the optical nonlinearity of pure PEDOT:PSS changes when mixed with MoS2. The Pauli blocking has been observed in MoS2/PEDOT:PSS NCFs. This leads to enhanced SA in NCF. The open-aperture Z-scan approach is used for the nonlinear optical research, and a nanosecond pulsed laser with a wavelength of 532 nm is used for the excitation. The findings obtained show the NCFs’ strong SA qualities.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0163588
Issue No: Vol. 134, No. 20 (2023)
-
- Optical Kerr nonlinearity of dielectric nanohole array metasurfaces with
different hole shapes near the anapole state-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203104
Abstract: At present, optical anapole resonances in nanostructures have attracted increasing attention due to the strong field confinement and substantially suppressed scattering. This study provides the results of three-dimensional finite-difference time-domain simulations exhibiting the possibility of the anapole state in high refractive index dielectric nanohole array metasurfaces having different profiles of the holes (square, hexagon, and octagon). Behavior of the effective optical Kerr nonlinearity of the metasurfaces in the vicinity of the anapole state is investigated. Depending on the geometry, the absolute value of the effective nonlinear Kerr coefficient of the metasurface may be up to three orders of magnitude greater than that of the unstructured film. A square transverse section of the nanohole is preferable for the optical Kerr effect in the holey metasurfaces. The effect of the random rotation of the square holes representing the metasurface irregularity on the optical nonlinearity is examined. As a result, the dielectric nanohole array metasurfaces display a concrete possibility to have the anapole state with large enhancement of the optical nonlinearity.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0170262
Issue No: Vol. 134, No. 20 (2023)
-
- Numerical analysis of the Brewster-electrical duo-effect for
multi-resonance tuning in THz absorber-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203105
Abstract: The excitation and tuning of multiple resonances with narrow spectral width based on Brewster's effect is possible in an ultrathin dual-band terahertz absorber. The angular variation establishes a monotonic relation with the frequency of some generated resonances offering tunability. Moreover, burying a graphene ring resonator beneath the metallic ring splits the resonance for providing the triple narrow absorption windows. The electrical modulation offers the feature of independent tunability in the generated third absorption band. Thus, the frequency ratio of the upper to lower spectral absorption peak can be modulated by the electrically tunable Fermi energy of graphene. Engraving the graphene resonator also enhances the incident angle based tunability by affecting a greater number of Brewster generated resonance peaks. The narrow line shape of the triple band absorption can enable refractive index sensing and the detection of extraneous elements in localized analyte samples. The detection of imidacloprid pesticide in wheat flour is performed by the implemented sensor. The numerical analysis is done for the design and analysis of the absorber structures to report the above facts.
PubDate: Wed, 29 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0175798
Issue No: Vol. 134, No. 20 (2023)
-
- Non-stoichiometry induced 2H–1T phase interfaces and room-temperature
ferromagnetism in defective molybdenum selenide-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203901
Abstract: Magnetic semiconducting materials offer tremendous prospects for spin electronics but is challenging to achieve room-temperature ferromagnetism with unambiguous origin. Herein, a non-stoichiometry strategy is proposed to induce tunable magnetization in MoSe2−x nanoflowers via vacancy-controlled 2H–1T phase transition. The resultant MoSe2−x exhibits robust room-temperature ferromagnetism with significant positive correlation to the content of 1T phase and 2H–1T interfaces. Significant magnetic hysteresis and Curie transition above room temperature have been achieved, confirming the ferromagnetic feature of MoSe2−x. To examine the origin of ferromagnetism, formation energy and spin-polarized calculations have been conducted, indicating that the Se vacancy is beneficial for the formation of the 1T phase and interfacial spin polarization. Localized magnetic moments induced at the 2H–1T interfaces exhibit enhanced magnetism as compared to the net moments from the 1T orbital splitting, giving rise to strong coupling bound magnetic polarons. This work not only advances the understanding on the origin of magnetism in magnetic semiconductors, but also provides an effective route to generate ferromagnetism by defect and/or interface engineering that could be applied to multiferroics, spintronics, and valleytronics.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0174268
Issue No: Vol. 134, No. 20 (2023)
-
- Collinear and noncollinear ferrimagnetic phases in Mn 4 N investigated by
magneto-optical Kerr spectroscopy-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203902
Abstract: Ferrimagnetic antiperovskite Mn 4N has received growing interest due to room-temperature observation of large perpendicular magnetic anisotropy, low saturation magnetization, and ultrafast response to external magnetic fields. Comprehensive understanding of the underlying magnetic structure is instrumental in design and fabrication of computer memory and logic devices. Magneto-optical spectroscopy provides deeper insight into the magnetic and electronic structure than magnetometry. Simulations of a magneto-optical Kerr effect in biaxially strained Mn 4N are performed using density functional theory and linear response theory. We consider three ferrimagnetic phases, two collinear and one noncollinear, which have been investigated separately by earlier studies. The simulated spectra are compared to measured magneto-optical data available in recent literature. One of the collinear ferrimagnetic phases is found to be consistent with the measured spectra. We show that an admixture of the noncollinear phase, which is the ground state of unstrained Mn 4N, further improves the agreement with measured spectra, and at the same time, it could explain the lower than predicted net moment and magnetic anisotropy observed in thin films on various substrates.
PubDate: Tue, 28 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0170621
Issue No: Vol. 134, No. 20 (2023)
-
- A 6 degrees of freedom electromagnetic–thermal–dynamic coupling model
for high-temperature superconducting levitation system-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 203903
Abstract: As the main merits, self-stabilization and no magnetic resistance make the high-temperature superconducting (HTS) magnetic levitation technology a crucial area for high-speed magnetic levitation development. To guarantee a stable operation of superconducting magnetic levitation systems, the dynamic characteristics of superconducting bulk materials occupy a significant place. However, in the previous research, there is still a lack of a simulation method that can describe 6 degree of freedom (DOF) motion of the superconductor. In this paper, an electromagnetic–thermal–dynamic coupling calculation model was established first. Then, the damping characteristics of 5-DOF superconducting levitation were experimentally tested, and the response analysis of the superconductor under 1–20 Hz excitation was carried out to explore the coupled motion relationship between the various degrees of freedom of the superconductor. In addition to the above, the operating conditions and primary resonance intervals that should be avoided by the HTS maglev system were identified. Additionally, a numerical simulation was conducted to investigate the dynamic response of the HTS maglev system under impact loads. All in all, this study explored the temperature rise conditions of superconducting bulk materials under excitation force through magnetic-thermal-force multi-physics coupling research. This 6-DOF model can provide a comprehensive simulation method for superconducting maglev systems in superconductor's motion behavior, attitude, and thermal state monitoring.
PubDate: Wed, 29 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0173279
Issue No: Vol. 134, No. 20 (2023)
-
- High field dielectric response in κ-Ga 2 O 3 films
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204101
Abstract: κ-Ga2O3 has been predicted to be a potential ferroelectric material. In this work, undoped Ga2O3 films were grown by either plasma-enhanced atomic layer deposition (PEALD) or metal organic chemical vapor deposition (MOCVD) on platinized sapphire substrates. 50 nm thick PEALD films with a mixture of κ-Ga2O3 and β-Ga2O3 had a relative permittivity of ∼27, a loss tangent below 2%, and high electrical resistivity up to ∼1.5 MV/cm. 700 nm thick MOCVD films with predominantly the κ-Ga2O3 phase had relative permittivities of ∼18 and a loss tangent of 1% at 10 kHz. Neither film showed compelling evidence for ferroelectricity measured at fields up to 1.5 MV/cm, even after hundreds of cycles. Piezoresponse force microscopy measurements on bare κ-Ga2O3 showed a finite piezoelectric response that could not be reoriented for electric fields up to 1.33 MV/cm.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0169420
Issue No: Vol. 134, No. 20 (2023)
-
- Spontaneous pattern of orthogonal ferroelectric domains in epitaxial KNN
films-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204102
Abstract: Lead-free piezoelectric (K, Na)NbO3 (KNN) is considered one of the promising candidates for the replacement of Pb(ZrxTi1−x)O3. Several studies underlined the issue of K and Na volatility with increasing deposition temperatures, leading to high leakage currents in thin films, which still represents a major drawback for applications. This paper shows how epitaxial growth with concomitant preferred orientation of KNN films on niobium-doped strontium titanate (Nb:STO) depends on growth temperature and substrate strain. A preferred out-of-plane polar (001) orientation of KNN is obtained at high temperatures (>600 °C), while (100) orientation is dominant for lower ones. The (001) orientation is forced out-of-plane due to the sizeable in-plane stress derived from a negative lattice mismatch of pseudo-cubic KNN with respect to the underlying cubic (001) Nb:STO substrate. Moreover, we show that K-Na deficiency and high leakage of epitaxial KNN films deposited at high temperatures are accompanied by the appearance of a pattern of orthogonal spontaneous ferroelectric domains aligned to the [100] and [010] directions of Nb:STO. This pattern, visible in secondary electron microscopy, piezoforce response microscopy, and conductive atomic force microscopy images, is uncorrelated to the surface morphology. Supported by reciprocal space mapping by x-ray diffraction, this phenomenon is interpreted as the result of strain relaxation via ferroelectric domain formation related to K-Na deficient films displaying a sizable and increasing compressive strain when grown on Nb:SrTiO3. Our findings suggest that strain engineering strategies in thin films could be used to stabilize specific configurations of piezo- and ferroelectric domains.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0171349
Issue No: Vol. 134, No. 20 (2023)
-
- Thermomechanic behavior of epitaxial GeTe ferroelectric films
-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204103
Abstract: A key development toward new electronic devices integrating memory and processing capabilities could be based on the electric control of the spin texture of charge carriers in semiconductors. In that respect, GeTe has been recently recognized as a promising ferroelectric Rashba semiconductor, with giant spin splitting of the band structure, due to the inversion symmetry breaking arising from ferroelectric polarization. Here, we address the temperature dependence of the ferroelectric structure of GeTe thin films grown on Si(111). We demonstrate the hysteretic behavior of the ferroelectric domain density upon heating/cooling cycles by low energy electron microscopy. This behavior is associated with an abnormal evolution of the GeTe lattice parameter as shown by x-ray diffraction. We explain these thermomechanical phenomena by a large difference of thermal expansion coefficients between the film and the substrate and to the pinning of the GeTe/Si interface. The accumulated elastic energy by the GeTe thin film during sample cooling is released by the formation of a-nanodomains with in-plane ferroelectric polarization components.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0173718
Issue No: Vol. 134, No. 20 (2023)
-
- Nonreciprocity and chirality hosted by ferromagnetic helical chains: Heat
generation vs spin filtering-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204301
Abstract: Motivated by the booming development of spintronics based on chiral helical microstructures, we employed the standard nonequilibrium Green’s function theory to study nonreciprocity and chirality of the heat generation and spin filtering in ferromagnetic helical chains. Our results demonstrate that magnetization, spin–orbit interaction, and nonstep electrostatic potential distribution by bias jointly determine nonreciprocity of the heat generation, and only spin–orbit interaction determines nonreciprocity of the spin-polarized current. Chirality of the heat generation and spin-polarized current is determined by both magnetization and spin–orbit interaction, and some quantitative relationships related to chirality were discovered. However, a transverse field can break these relations and suppress heat generation significantly and modulate nonreciprocity and chirality of the spin-polarized current effectively. By further simulating the critical electrostatic potential distribution, we found with the transverse field applied, compared to the case with zero temperature, that the finite temperature less than one characteristic phonon energy can suppress nonreciprocity of the heat generation while enhancing that of the spin filtering. In terms of chirality, compared to the left-handed helical structure, the right-handed one is more advantageous for designing spin filtering diodes.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0174181
Issue No: Vol. 134, No. 20 (2023)
-
- Semi-classical Monte Carlo study of the impact of tensile strain on the
performance limits of monolayer MoS 2 n-channel MOSFETs-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204302
Abstract: The effects of tensile strain and contact transmissivity on the performance limits of monolayer molybdenum disulfide ( MoS 2) nanoscale n-channel MOSFETs are studied using a semi-classical Monte Carlo method. Density functional theory calculations were performed to parametrize the electronic band structure of MoS 2 subject to tensile and shear strain. Tensile strain decreases the bandgap, increases the inter-valley band-edge energy separation between the light-mass K-valleys and heavier-mass Q-valleys, and decreases the K-valley effective mass in a way that depends on the direction and the amount of the applied strain. Biaxial tensile strain and uniaxial tensile strain along the x- or y-directions are found to have the largest effect. In bulk materials, low-field phonon-limited electron mobility is enhanced, peak and saturation drift velocities are increased, and high-field negative differential resistance becomes more pronounced. Both 200 and 15 nm gate length MoS 2 MOSFETs with end-contacts with ideal (unity) and more realistic (significantly sub-unity) contact interface transmissivity were simulated. These MoS 2 devices exhibited substantial sensitivity to strain with ideal contact transmissivity, and more so for the 15 nm quasi-ballistic device scale than 200 nm long-channel devices. However, the results showed much less strain sensitivity for devices with more realistic contact transmissivities, which may be good or bad depending on whether strain-insensitive or strain-sensitive performance is desired for a particular application and may be possible to modify with improved contact geometries.
PubDate: Tue, 28 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0177621
Issue No: Vol. 134, No. 20 (2023)
-
- Acoustic rotation of multiple subwavelength cylinders for
three-dimensional topography reconstruction-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204501
Abstract: Accurate rotation of microparticles is of great significance in micro-rotors, multi-angle microscopic observation, microbial three-dimensional phenotyping, and microsystem assembly. However, most methods can only rotate a single object, thus limiting the throughput. In this study, we realized the simultaneous rotation of many trapped and aligned subwavelength glass cylinders inside an evanescent wave field excited by a resonant phononic crystal plate. The unique feature of the rotation lies in its periodic distribution as well as the rotation axis being perpendicular to the acoustic axis. The rotary power originates from viscous torque generated by the evanescent wave-induced near-boundary acoustic streaming's asymmetry distribution on the trapped cylinder. Furthermore, the three-dimensional topographies of rotated cylinders can be reconstructed from the microscopic images under different rotating angles. Our findings can pave the way toward developing simple, disposable, and scalable microfluidic devices for massive subwavelength acoustic rotation by carefully designing acoustic metamaterials.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0167996
Issue No: Vol. 134, No. 20 (2023)
-
- Atomic and electronic origin of robust off-state insulation properties in
Al-rich Al x Te y glass for ovonic threshold switching applications-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204502
Abstract: Ovonic threshold switching (OTS) selectors play a critical role in suppressing the sneak-path current of three-dimensional crossbar integration circuits. Compared to conventional nonmetal-telluride OTS selectors, selectors based on AlxTey glass are found to have both satisfactory on-state current and selectivity. However, it is unclear why the Al-rich AlxTey glass-based OTS selectors have robust insulation properties for reducing the off-state current. This work reveals the structure–property correlations of amorphous AlxTey at the atomic scale by first-principles calculations. It is found that the stoichiometric Al2Te3 glass tends to have a clean bandgap owing to the covalent and dative bonds formed by non-equivalent sp3-hybridized Al orbitals and the lone-pair electrons of Te. Unexpectedly, for Al-rich AlxTey glass (Al2.21Te2.79), the Al–Al bonds formed by redundant Al-atoms have an integrated crystal orbital bond index (ICOBI) of 0.8–0.9, which is much larger than that of Al–Al bonds in pure metals (0.227), indicating they are covalent. It is the covalent Al–Al bonds that ensure the robust insulation characteristics of Al-rich AlxTey glass, while the Te–Te interaction in the Al-poor AlxTey glass (Al1.79Te3.21) produces midgap states, thereby reducing the insulativity. The presented atomic and electronic pictures here will provide useful theoretical insights for designing OTS selectors with improved performances.
PubDate: Thu, 30 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0168408
Issue No: Vol. 134, No. 20 (2023)
-
- A method to determine arsenic concentration in drinking water based on
proton gradient and conductance measurements in filter paper media-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204901
Abstract: This work describes a novel technique for the measurement of inorganic arsenic in water by generating arsine gas and detecting the conductivity of moving protons, H+ (aqueous or aq), produced by the reaction: Ag+ (aq) + AsH3 (gas, g) → AgAsH2 (solid, s) + H+ (aq). The detection is based on an electrochemical gradient of protons in a confined porous substrate (filter paper) and measures the change in the conductance due to the higher mobility of H+ compared to other ions. The conductance was measured with a pair of silver electrodes attached to opposite sides of the substrate with a bipolar pulse conductance technique. The method is established in theory and in practice. The theoretical equation for conductance change shows that a constant increase in conductance is directly proportional to the As(total) concentration. The method is validated with a standard reference material and applied to the measurement of the groundwater sample.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0175988
Issue No: Vol. 134, No. 20 (2023)
-
- Evaluation of uncertainty in antineutrino spectra normalization
calculations for advanced nuclear reactor monitoring-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 204902
Abstract: Antineutrino detection systems have been envisioned as an important aspect of safeguarding the next generation of nuclear reactors, especially considering designs utilizing exotic fuel cycles. Deployment of antineutrino detection systems for safeguarding applications is hindered by the uncertainties associated with the calculations required for antineutrino spectra measurements and predictions. The focus of this work is to assess the impact of system components on antineutrino spectra normalization uncertainties and their significance in reactor power monitoring sensitivity. The dominant limitation in antineutrino detection calculations is typically the uncertainty associated with a cosmogenic background. This limitation becomes more pronounced when signals are weak, although the issue is mitigated in larger reactors due to their stronger source strength. Additionally, antineutrino emission uncertainties vary with the isotopic composition of the reactor fuel. Unconventional fuel cycles, featuring less common fissioning isotopes, such as Pu-240, introduce larger antineutrino yield uncertainties. The findings from this study suggest that future research on safeguard-targeted antineutrino detection should prioritize background mitigation, particularly when background simulation is necessary. Advanced nuclear reactor designs have a major influence on background understanding and successful system implementation.
PubDate: Wed, 29 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0157503
Issue No: Vol. 134, No. 20 (2023)
-
- Direct current conductance and 1/ f -noise in cellulose
nanofiber–multi-walled carbon nanotube composites for applications in
flexible electronic devices-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205101
Abstract: We report on the studies of conduction mechanism, direct current conductance, and 1 f-noise of cellulose nanofiber (CNF) and multiwalled carbon nanotube (MWCNT) composites. The composites were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. The temperature- and voltage-dependence of the dc conductance Σ were, respectively, probed to investigate the charge transport mechanism and the electrical response of the composite. At room temperature, the increase in Σ with wt. % of MWCNT ϕ showed typical percolation behavior. The Σ − T behavior was fitted to the combination of one-dimensional variable range hopping and the fluctuation-induced tunneling, which were attributed to hopping of charge carriers through 1D MWCNTs and the tunneling of charge carriers between the bundles of MWCNTs, respectively. The non-Ohmic electrical conduction was characterized by the onset voltage V 0 ( T ) which scaled with Ohmic conductance Σ 0 as V 0 ( T ) ∼ Σ 0 ( T ) x T, with x T being the onset exponent increased with ϕ. A scaling description based on the data collapse method was adopted to find the parameters V 0 ( T ) and x T. The noise power spectrum S V ( f ) followed the relation S V ( f ) ∼ V β with two different power-laws: β 1 in the Ohmic and β 2 in the non-Ohmic region ( β 1 > β 2). Interestingly, this change in power-laws occurs at the same V 0 ( T ) obtained from Σ − V curves. A simple model was proposed to explain the noise behavior after V 0 ( T ). It is expected that such electrical characterization of CNF-MWCNT nanopaper composite would open up their possibility of application in flexible electronic devices, intelligent networks, sensors, and actuators.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0173432
Issue No: Vol. 134, No. 20 (2023)
-
- Limits of Ohm’s law in ultra-pure metals with almost ideal crystal
lattices-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205102
Abstract: By electric transport measurements on high-purity bulk molybdenum single crystals at helium-temperature, it is shown that when approaching the ideal metallic crystal structure, there are deviations from Ohm’s law that can exceed 30% even at low current densities ≅ 3 A / m m 2. This is due to the intrinsic circular magnetic field of the measuring current in the range of B ≅ 1 mT, which generates a magnetoresistance according to the two-band conduction model. With increasing lattice vibrations and/or crystal defects, this inherent uncertainty finally reduces to immeasurably small values. Finally, Ohm’s law for a nearly ideal lattice structure can be strictly exact only in the theoretical limiting case of an infinite lattice plane, because then the magnetic fields of all electrons of the current compensate to zero.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0173486
Issue No: Vol. 134, No. 20 (2023)
-
- Morphology and symmetry driven by lattice accommodation in polycrystalline
bcc–fcc core–shell metallic nanoparticles-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205301
Abstract: Body-centered-cubic–face-centered-cubic (bcc–fcc) multi-metallic nanoparticles (NPs) associating a single-crystal core (Fe, FeCo alloys, etc.) with a polycrystalline noble metal shell (Au, AuAg alloys, etc.) are perfectly symmetrical or more irregular, even dramatically dissymmetrical, yet presenting a good crystalline organization. Here, a combination of experimental analysis and theoretical symmetry analysis is proposed, in order to provide a unified description of the observed morphologies (Fe–Au and Fe–AuAg systems), whatever their symmetry, and predict some morphology variability in a population of NPs. First, the central role of the crystal lattice accommodation is comprehensively analyzed from the experimental Fe–AuAg system. The two possible bcc–fcc epitaxial relationships generate a core–shell interface in the shape of a truncated rhombic dodecahedron. This results in two different types of grains in the shell, which are elastically accommodated between them by an equal distribution of twins and low-angle grain boundaries, however, at the cost of internal stresses. At the same time, symmetry breaking results from two possible growth variants originating from the Nishiyama–Wasserman epitaxial relationships. The shell grains fit together in a nanopuzzle-like organization, resulting in a large number of possible arrangements distributed in 13 different point groups of symmetry, all of lower order than the core symmetry (highest order of cubic symmetry). If the variants are randomly distributed, the probability for the NP to be asymmetric (group 1) is 80%. The dissymmetrical development of the NPs is then discussed. Extending this approach to other core shapes succeeds in predicting dissymmetrical or dramatically off-centered morphologies experimentally observed in Fe–Au NPs.
PubDate: Thu, 30 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0169818
Issue No: Vol. 134, No. 20 (2023)
-
- Charge state transition levels of Ni in β -Ga 2 O 3 crystals from
experiment and theory: An attractive candidate for compensation doping-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205701
Abstract: Nickel-doped β-Ga2O3 crystals were investigated by optical absorption and photoconductivity, revealing Ni-related deep levels. The photoconductivity spectra were fitted using the phenomenological Kopylov and Pikhtin model to identify the energy of the zero-phonon transition (thermal ionization), Franck–Condon shift, and effective phonon energy. The resulting values are compared with the predicted ones by first-principle calculations based on the density functional theory (DFT). An acceptor level (0/−) of 1.9 eV and a donor level (+/0) of 1.1 eV above the valence band minimum are consistently determined for NiGa, which preferentially incorporates on the octahedrally coordinated Ga site. Temperature-dependent resistivity measurements yield a thermal activation energy of ∼2.0 eV that agrees well with the determined Ni acceptor level. Conclusively, Ni is an eminently suitable candidate for compensation doping for producing semi-insulating β-Ga2O3 substrates due to the position of the acceptor level (below and close to the mid-bandgap).
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0173761
Issue No: Vol. 134, No. 20 (2023)
-
- In situ insight into temperature-dependent microstructure evolution of
carbon doped phase change materials-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205702
Abstract: Carbon-doped Ge2Sb2Te5 (CGST) is a potential candidate in phase change random access memory (PCRAM) with superb thermal stability and ultrahigh cycle endurance. Direct observation of the microstructure evolution of CGST is desirable to uncover the phase transformation mechanism on the relationship of nucleation/crystalline behaviors of the crystalline phase at elevated temperatures and the pristine amorphous phase at room temperature. Here, we investigate the structural evolution of CGST using combined in situ techniques. Our in situ x-ray diffraction and ellipsometry results demonstrate that CGST exhibits a much higher phase transition temperature than undoped one. Temperature-dependent in situ transmission electron microscopy observations further reveal that carbon doping plays a critical role in tailoring the properties of GST by tuning the stochasticity of nucleation/crystallization, stabilizing amorphous and crystalline GST via isolating and refining the grain size at room temperature and elevated temperature. Our work provides detailed information for understanding the microscopic origin of crystallization kinetics of carbon-doped phase change materials toward high-performance PCRAM.
PubDate: Wed, 22 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0179391
Issue No: Vol. 134, No. 20 (2023)
-
- First-principles prediction of energy bandgaps in 18-valence electron
semiconducting half-Heusler compounds: Exploring the role of exchange and
correlation-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205703
Abstract: The choice of exchange functional is a critical factor in determining the energy bandgap of semiconductors. Ab initio calculations using different exchange functionals, including the conventional generalized-gradient approximation (GGA) functionals, meta-GGA functionals, and hybrid functionals, show significant differences in the calculated energy bandgap for semiconducting half-Heusler compounds. These compounds, which have 18 valence electrons per unit cell, are of great interest due to their thermoelectric properties, making them suitable for energy conversion applications. In addition, accounting for electronic correlations using the G W method also affects the calculated energy bandgaps compared to standard GGA calculations. The variations in calculated energy bandgaps are specific to each material when using different functionals. Hence, a detailed investigation of the electronic properties of each compound is necessary to determine the most appropriate functional for an accurate description of the electronic properties. Our results indicate that no general rules can be established and a comparison with experimental results is required to determine the most appropriate functional.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0178165
Issue No: Vol. 134, No. 20 (2023)
-
- Reduction of phosphorus diffusion in bulk germanium via argon/phosphorus
co-implantation and RTA annealing-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205704
Abstract: Germanium has received increased research interest for use in next-generation CMOS technology as its high carrier mobilities allow for enhanced device performance without further device scaling. Fabrication of high-performance NMOS Ge devices is hindered by high diffusivity and low activation of n-type implanted dopants. While the high solid solubility of P in Ge makes it an ideal dopant, its diffusion mechanism is poorly understood and results in heavy tradeoffs between implanted dopant diffusion and electrical activation. In this study, we demonstrate the suppression of in-diffusion of implanted P via a co-implantation with Ar. Diffusivity of implanted P species and their activation is investigated over a wide range of annealing temperatures and times. P diffusion was explored by secondary-ion-mass-spectrometry and the diffusivity of P was extracted by solving the 2D diffusion equation using the Crank–Nicolson method, and the dopant electrical activation was extracted from the Hall effect measurements. The co-implantation of P with Ar entirely suppresses P in-diffusion up to annealing temperatures as high as 700 °C but at the cost of its reduced electrical activation. Extracted diffusivity reveals a highly correlated exponential relationship with annealing. P activation energy was extracted from Arrhenius behavior. A 450 °C/10 min annealing of P implant shows negligible in-diffusion of P with the activation as high as 70%. RTA processing of the Ar/P co-implanted sample at 750 °C for 1 min results in a negligible P in-diffusion and an electrical activation of 20%.
PubDate: Tue, 28 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0161639
Issue No: Vol. 134, No. 20 (2023)
-
- Electrodeless method for ultra-low mobility with carrier-resolution of
nanochannel-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205705
Abstract: As the channel lengths of electronic devices are scaled down to the nanometer range, the conventional methods to evaluate charge-carrier mobility approach a technical limit that is imposed by interfering effects of the electrode and forcing field. In this study, we demonstrate that electron spectroscopy provides additional (yet hidden) information on unipolar charge transport, which is free from conventional problems. We demonstrate that the estimated effective diffusion current through the target sample allows the measurement that is precise enough (10−4 cm2/V s) to obtain the mobility of electrons μelectron and holes μhole in nanolength organic channels. Using this method, we show how μelectron and μhole are correlated with the local structural order of poly(3-hexylthiophene) at the nanoscale. This method enables in situ charge-resolved observations of μelectron and μhole by eliminating the need for electrode and forcing field and will help to expand our understanding of charge conduction in nanoscale materials.
PubDate: Thu, 30 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0167472
Issue No: Vol. 134, No. 20 (2023)
-
- Quantitative x ray phase contrast imaging of oblique shock
wave–interface interactions-
Free pre-print version: Loading...Rate this result: What is this?Please help us test our new pre-print finding feature by giving the pre-print link a rating.
A 5 star rating indicates the linked pre-print has the exact same content as the published article.
First page: 205901
Abstract: Oblique shock wave–interface interactions of gases and liquids have been extensively studied in shock tubes using optical methods to measure equation-of-state (EOS) parameters. However, this is difficult with solids due to their opaqueness to visible light. X ray phase contrast imaging (XPCI) has the penetrative strength to probe solids while still being sensitive to mass density and enhancing the visibility of material boundaries. We investigate the accuracy and repeatability of measuring the mean value of the average mass density (areal density divided by thickness) over region S ( B S) and flow deflection angle ( θ) from XPCI images of a sample. To that end, a Hough transform-based method for measuring θ is developed. To measure B S, the XPCI image intensity probability density function (PDF) is modeled accounting for the spatial distribution of x ray energy, scintillator response, and pulse-to-pulse variation in the x ray intensity. In addition, a Monte Carlo-based algorithm for computing the B S PDF is developed. Both methods are validated on an impact-generated oblique shock wave interacting at a solid polymer-to-polymer interface. This is accomplished through a comparison to hydrodynamic simulations using well-established EOS. Under the modeling framework for the XPCI image intensity, B S is computed with an accuracy of < 0.1% and precision of 3%–5%, while θ has an uncertainty of 0.2 °, respectively. This shows that the XPCI-based model that is developed here could be an invaluable tool for high-fidelity testing of hydrodynamic models in shock polar configurations.
PubDate: Mon, 27 Nov 2023 00:00:00 GMT
DOI: 10.1063/5.0174086
Issue No: Vol. 134, No. 20 (2023)
-
