摘要:
In this paper, we propose a regularized lattice Boltzmann model for one-dimensional nonlinear scalar hyperbolic conservation laws which can convert to convection–diffusion equation through introducing a dissipation term. Then, a rigorous Chapman–Enskog analysis is conducted to show that this models can recover the correct governing equation. Finally, we also conduct some simulations to test the model and find that the numerical results not only agree with the exact solutions but also exhibits superior performance in solving hyperbolic conservation laws with discontinuous initial conditions.
In this paper, we propose a regularized lattice Boltzmann model for one-dimensional nonlinear scalar hyperbolic conservation laws which can convert to convection–diffusion equation through introducing a dissipation term. Then, a rigorous Chapman–Enskog analysis is conducted to show that this models can recover the correct governing equation. Finally, we also conduct some simulations to test the model and find that the numerical results not only agree with the exact solutions but also exhibits superior performance in solving hyperbolic conservation laws with discontinuous initial conditions.
作者:
Lam, Leo S. I.;Deng, Hai-Yao;Zhang, Wei-Bing;Nwankwo, Udoka;Xiao, Chu;...
期刊:
Physical Review E,2025年111(4) ISSN:2470-0045
通讯作者:
Ruan, HH;Lee, CS;Lam, CH
作者机构:
[Ruan, Haihui; Nwankwo, Udoka; Lam, Leo S. I.] Hong Kong Polytech Univ, Dept Mech Engn, Hong Kong, Peoples R China.;[Deng, Hai-Yao] Cardiff Univ, Sch Phys & Astron, 5 Parade, Cardiff CF24 3AA, Wales.;[Zhang, Wei-Bing] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Peoples R China.;[Lee, Chun-Shing; Lee, CS; Yip, Cho-Tung; Xiao, Chu] Harbin Inst Technol, Dept Phys, Shenzhen 518055, Peoples R China.;[Lam, Chi-Hang; Lam, CH] Hong Kong Polytech Univ, Dept Appl Phys, Hong Kong, Peoples R China.
通讯机构:
[Lee, CS ; Ruan, HH ; Lam, CH ] H;Hong Kong Polytech Univ, Dept Mech Engn, Hong Kong, Peoples R China.;Harbin Inst Technol, Dept Phys, Shenzhen 518055, Peoples R China.;Hong Kong Polytech Univ, Dept Appl Phys, Hong Kong, Peoples R China.
摘要:
The physics of glass has been a significant topic of interest for decades. Dynamical facilitation is widely believed to be an important characteristic of glassy dynamics, but the precise mechanism is still under debate. We propose a lattice model of glass called the facilitated random walk (FRW). Each particle performs a continuous time random walk in the presence of its own random local kinetic constraints. The particles do not interact energetically. Instead, they interact kinetically with a hopping rate resampling rule under which motions of a particle can randomly perturb the local kinetic constraints of other particles. This dynamic interaction is reversible, following a rate restoration rule. A step-by-step reversal of the particle motions exactly restores the previous constraints, modeling randomness quenched in the configuration space of glass. The model exhibits stretched exponential relaxation and dynamical heterogeneity typical of glasses. Despite the lack of an explicit facilitation rule, the FRW shows facilitation behaviors closely analogous to those of the kinetically constrained models (KCM). The FRW is a coarse-grained version of the distinguishable particle lattice model (DPLM) and this exemplifies that compatible defect and atomistic models can complement each other in the study of glass.
摘要:
Two-dimensional (2D) Janus materials have received significant attention due to their unique physical structure and superior electronic and optical properties. Here, we investigate the diode performance of 2D Janus WSeTe or MoSeTe vertical contact with 2D 1T-MoTe 2 using ab initio quantum transport simulations. When the Te atomic layer of WSeTe or MoSeTe contacts with 1T-MoTe 2 (known as type-A heterojunction), the contact interface exhibits significant Fermi level pinning (FLP), resulting in a larger Schottky barrier height (SBH). Through interlayer flipping, the Se atomic layer of WSeTe or MoSeTe comes into contact with 1T-MoTe 2 (known as type-B heterojunction), FLP at the contact interface will be significantly suppressed, resulting in obvious reduction of the SBH. Therefore, Schottky diodes based on type-B heterojunction exhibit superior performances with higher rectification ratio and larger photocurrent compared to Schottky diodes based on type-A heterojunction.
期刊:
Journal of Lightwave Technology,2025年43(7):3506-3512 ISSN:0733-8724
作者机构:
["Zhou, Miaofang; Cao, Guangtao; Zhang, Ling; Liu, Junyu; Guan, Yuhong"] College of Physics and Electronic Science, Changsha University of Science and Technology, Changsha, China;[Zhou, Xinshun] Hubei university of technology engineering and technology college, Wuhan, China
摘要:
We propose a holes-assisted few-mode fiber (HFMF) consisting of a GeO2 doped SiO2 core, a SiO2 cladding, and three strategically positioned holes. The incorporation of these holes produces a significant contribution in separating the non-degenerated linearly polarized (LP) modes and degenerated spatial modes, thereby considerably improving the mode spacing. Numerical simulation results demonstrate that our designed HFMF can support 12 spatial modes with the min effective index difference between adjacent non-degenerated LP modes (Δneff) larger than 1.65 × 10−3 and the min effective index difference between adjacent degenerated spatial modes (δneff) above 2.64 × 10−4 at the wavelength of 1550 nm, breaking through the trade-off between mode spacing and the number of modes. Furthermore, the min Δneff and min δneff of exceeding 1.63 × 10−3 and 2.44 × 10−4 can be achieved over the whole C and L bands, respectively. The new designed fiber is specifically tailored for less MIMO mode division multiplexing (MDM), enabling significant capacity enhancement in optical communication systems.
摘要:
Efficiently manipulating charge transport at the molecular level is critical to developing multifunctional and responsive molecular electronic devices. Here, we report the first electroresponsive tristate switch in a supramolecular circuit, overcoming the binary limitation and enabling richer logic encoding, governed solely by a bias voltage (electric field). At low electric fields, p -phenylenediamine (PPD) molecules exhibit a high-conductance state, which transitions successively to two distinct low-conductance states as the external electric field strength increases. This precise control of supramolecular junctions through electric field manipulation achieved an on/off ratio G H /G L of ∼1.25×10 3 , which is one of the largest values reported to date. Flicker noise analysis and density functional theory calculations reveal the intrinsic mechanism for the observation, i.e ., electric field promoting the formation of trimer supramolecular junctions leads to the striking on/off ratio. These findings provide new insights into the design of molecular circuits with tunable conductance, paving a way for the design of molecular computation, memory devices, and sensors.
通讯机构:
[Long, MQ ] C;Cent South Univ, Sch Phys, Changsha 410083, Peoples R China.;Xinjiang Univ, Sch Phys Sci & Technol, Urumqi 830046, Peoples R China.
摘要:
Conventional thermoelectric conversion based on charge transport faces significant challenges due to inherent limitations, such as a low power factor, inevitable Joule heating, and high thermal conductivity. To address these challenges, spin caloritronics offer a promising pathway for thermoelectric conversion based on the spin degree of freedom, which has attracted considerable interest because of its low energy consumption and high response speed. In this study, we systematically investigates the gate-voltage-tunable spin caloritronic properties of transition metal (Fe/Cr)-doped Janus MoSeTe nanoribbons through combined non-equilibrium Green's function and density functional theory. These results reveal that Cr-doped Janus MoSeTe devices demonstrate a perfect spin Seebeck effect with pure spin current under specific gate voltages. The Fe-doped system exhibits two negative differential thermal resistance peaks and achieves 100% thermal-driven spin polarization through effective spin filtering. Notably, both the magnitude and polarity of these negative differential thermal resistance peaks can be controlled via gate voltage, which is attributed to the fact that the gate voltage can modulate the spin-resolved transmission spectrum. Furthermore, these devices demonstrate a significant spin figure of merit (ZT(sp,max)similar to 42) near the Fermi level at T = 300 K. These findings highlight the potential for developing high-efficiency spin caloritronic devices and thermal management applications utilizing Fe/Cr-doped MoSeTe nanoribbons under a specific gate voltage.
摘要:
SmCo12, with its large magnetic energy product, is a highly promising high-temperature permanent magnet that has attracted significant attention. However, the widely existing ThMn12-type crystal structure in this system faces serious stability problem, which significantly hinders its practical engineering applications. Exploring a novel SmCo12 structure that combines stability and excellent magnetic properties is crucial for breaking through this bottleneck. In this study, the metastable phases of the SmCo12 system are systematically investigated by using a local particle swarm optimization algorithm combined with first-principles calculations. The theoretical calculations reveal a hexagonal phase structure (space group P<overline>31m) with a formation energy 90 meV/atom lower than that of the conventional ThMn12-type SmCo12. Its phonon spectrum shows no imaginary frequencies and its structure remains stable during Nos & eacute;-Hoover thermostat simulations at 1200 K, confirming its dynamic stability and thermodynamic stability. The electronic structure reveals that this structure exhibits metallic characteristics, with a total magnetic moment of as high as 21.81 mu(B)/f.u. and a magnetocrystalline anisotropy constant of up to 11.10 MJ/m(3), significantly exceeding similar high-cobalt-content Sm-Co systems. Furthermore, theoretical predictions indicate that the hexagonal phase SmCo12 structure exhibits exceptionally outstanding magnetic properties, with maximum energy product, anisotropy field, and Curie temperature reaching 54.56 MGOe, 15.01 MA/m, and 1180 K, respectively. The newly discovered hexagonal SmCo12 phase provides a novel direction for solving the stability problem of the ThMn12-type structure.
摘要:
Magnetic anisotropy (MA) is one of the key properties in two-dimensional (2D) magnetic materials, as it determines the type of magnetism and its stabilities. Since the discovery of intrinsic 2D magnetic materials, the MA has garnered significant attention, and more efforts have been devoted to its effective manipulation. In this study, we construct van der Waals heterostructures by overlaying the CrI3 monolayer on five kinds of MXene layers. Our first-principles calculations reveal that the MA of the CrI3 layer can be effectively tuned through the formation of CrI3/MXene heterostructures. Notably, the magnetic anisotropy energy (MAE) can be enhanced by up to 71% in CrI3/Ti2CO2. Furthermore, by applying biaxial strain to CrI3/MXene, we achieve a wide-range regulation of MAE, and even small strain can induce a switch in the spin direction between in-plane and out-of-plane orientations. This pronounced response of MAE to strain should be attributed to the tunable interfacial effects. Our findings provide enlightenment to manipulate the MAE of 2D magnetic materials effectively through the synergistic effect of interfacial effects and strain. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/).
期刊:
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY,2025年88:102791 ISSN:0364-5916
通讯作者:
Du, Y;Fabrichnaya, O
作者机构:
[Du, Yong; Yang, Lianfeng; Liu, Yuling] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Zeng, Yinping] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.;[Fabrichnaya, Olga] TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.;[Zhang, Ligang] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Peoples R China.
通讯机构:
[Du, Y ] C;[Fabrichnaya, O ] T;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.
摘要:
Thermodynamic investigation of the Na 2 O-SiO 2 system is extremely significant for the silicate glass industry and the control of Na 2 O balance in the input materials of blast furnaces. The Na 2 O-SiO 2 system has been thermodynamically assessed numerous times in the previous studies. However, the phase equilibria in the Na 2 O-rich side remain inadequately described. Consequently, the Na 2 O-SiO 2 system was reassessed by the CALPHAD approach in the present work. The liquid phase was described by using the two-sublattice partially ionic liquid model (Na +1 ) P (O −2 ,SiO 4 −4 ,SiO 2 ) Q and six intermediate compounds were treated as stoichiometric compounds due to their limited solid solubilities. A set of self-consistent thermodynamic parameters was then obtained, and the experimental phase diagram data and thermodynamic properties can be satisfactorily reproduced by the calculation within the experimental errors. The present thermodynamic parameters contribute to the composition design of silicate glass and the formulation of input materials in blast furnaces.
Thermodynamic investigation of the Na 2 O-SiO 2 system is extremely significant for the silicate glass industry and the control of Na 2 O balance in the input materials of blast furnaces. The Na 2 O-SiO 2 system has been thermodynamically assessed numerous times in the previous studies. However, the phase equilibria in the Na 2 O-rich side remain inadequately described. Consequently, the Na 2 O-SiO 2 system was reassessed by the CALPHAD approach in the present work. The liquid phase was described by using the two-sublattice partially ionic liquid model (Na +1 ) P (O −2 ,SiO 4 −4 ,SiO 2 ) Q and six intermediate compounds were treated as stoichiometric compounds due to their limited solid solubilities. A set of self-consistent thermodynamic parameters was then obtained, and the experimental phase diagram data and thermodynamic properties can be satisfactorily reproduced by the calculation within the experimental errors. The present thermodynamic parameters contribute to the composition design of silicate glass and the formulation of input materials in blast furnaces.
摘要:
Non-Abelian multiband topology, characterized by frame charges, has garnered significant attention in the past few years. The non-Abelian frame charge evolution can be deduced from the rotation of the multiband in momentum space, which can promise potential applications based on the dynamic non-Abelian topological effects. In this work, based on two-dimensional phononic crystals, we directly observe the eigenstate frame rotation to verify non-Abelian band topology, which further predicts the location of the corner modes in this multigap system. These one-dimensional edge states of band gaps or bulk band continuum that induce zero-dimensional corner states are also confirmed experimentally. The corresponding higher-order topology is examined by detecting the acoustic responses in a finite phononic crystal sample. Our work provides experimental evidence for the unique non-Abelian band topology and a convenient platform for studying novel higher-order topological matter phases.
作者机构:
[Qing Su] School of Computer Science and Technology, Changsha University of Science and Technology, 410114, Changsha, China;[Xin Wang] School of Physics and Electronic Science, Changsha University of Science and Technology, 410114, Changsha, China;[Wei Wang] School of Computer Science and Technology, Changsha University of Science and Technology, 410114, Changsha, China<&wdkj&>School of Physics and Electronic Science, Changsha University of Science and Technology, 410114, Changsha, China
会议名称:
Advanced Intelligent Computing Technology and Applications: 21st International Conference, ICIC 2025, Ningbo, China, July 26–29, 2025, Proceedings, Part I
摘要:
To address pseudo-changes caused by background variations in remote sensing change detection, a dual-branch difference-enhanced network (DDECNet) with an efficient cross-attention mechanism is proposed. The Dual-Temporal Interaction Augmentation Module (DTIAM) enhances semantic consistency during bi-temporal feature interaction through temporal state alignment. The Difference Feature Enhancement and Supplementary Module (DFESM) reduces information loss in differential feature extraction using dual-branch feedback mechanisms for bidirectional temporal state correction. Differential features and bi-temporal interaction features are integrated via the Efficient Cross-Attention (ECA) mechanism, which establishes adaptive attention weighting through multi-scale aggregation to enhance key region identification. Evaluations on WHU-CD, SYSU-CD, and LEVIR-CD demonstrate superior performance, achieving F1-score improvements of 0.48% and 0.78% over existing methods on WHU-CD and SYSU-CD, respectively, while maintaining competitive accuracy on LEVIR-CD. The method achieves state-of-the-art performance, with code available at: https://github.com/decoder0112/DDECNet .
作者机构:
Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments, Changsha University of Science & Technology, Changsha 410114, China;School of Physics & Electronic Science, Changsha University of Science & Technology, Changsha 410114, China;Author to whom correspondence should be addressed.;[Wen, Yongjun; Zhou, Jiake; Zhang, Zhao] Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>School of Physics & Electronic Science, Changsha University of Science & Technology, Changsha 410114, China;[Tang, Lijun] Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>School of Physics & Electronic Science, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
通讯机构:
[Lijun Tang] H;Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>School of Physics & Electronic Science, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
摘要:
Aiming at the problems that the semantic representation of information extracted by the shallow layer of the current remote sensing image scene classification network is insufficient, and that the utilization rate of primary visual features decreases with the deepening of the network layers, this paper designs a multi-scale reverse master–slave encoder network (RMSENet). It proposes a reverse cross-scale supplementation strategy for the slave encoder and a reverse cross-scale fusion strategy for the master encoder. This not only reversely supplements the high-level semantic information extracted by the slave encoder to the shallow layer of the master encoder network in a cross-scale manner but also realizes the cross-scale fusion of features at all stages of the master encoder. A multi-frequency coordinate channel attention mechanism is proposed, which captures the inter-channel interactions of input feature maps while embedding spatial position information and rich frequency information. A multi-scale wavelet self-attention mechanism is proposed, which completes lossless downsampling of input feature maps before self-attention operations. Experiments on open-source datasets RSSCN7, SIRI-WHU, and AID show that the classification accuracies of RMSENet reach 97.41%, 97.61%, and 95.9%, respectively. Compared with current mainstream deep learning models, RMSENet has lower network complexity and excellent classification accuracy.
期刊:
IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS,2025年:1-1 ISSN:0278-0070
作者机构:
[Quan Xu] School of Microelectronics and Control Engineering, Changzhou University, Changzhou, China;[Fei Yu; Shaoqi He; Wei Yao; Shuo Cai] School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha, China
摘要:
By integrating memristors into a Hopfield neural network (HNN), a diverse range of dynamical behavior can be generated, which has significant implications for modeling and biomimetic applications of artificial neurons. However, research on the firing dynamics of HNNs remains relatively limited. In response, a memristive tri-neurons Hopfield neural network (MTN-HNN) was constructed, with the synapse of the second neuron replaced by the proposed memristor. A theoretical and experimental investigation of the dynamics of this neural network was conducted using general analytical tools, such as phase diagrams, Lyapunov exponents, bifurcation diagrams, and others. Experimental results indicate that the dynamics of the MTN-HNN is influenced by the internal parameters of the memristor, enabling the network to extend attractors in up to two directions and thereby form grid multi-scrolls. Notably, the MTN-HNN exhibits various firing modes, including periodic and chaotic bursting. Finally, an encryption scheme was proposed to demonstrate the potential of the MTN-HNN, and both the custom digital circuits and the encryption scheme were successfully implemented on a Field-Programmable Gate Array (FPGA).
关键词:
Auto-adjust JFET (AD-JEFT);Breakdown voltage ( BV );LDMOS with AD-JEFT (ADJ-LDMOS);Saturation current ( I (dsat) )
摘要:
A 1200V 4H–SiC lateral double-diffused MOSFETs (LDMOS) with embedded auto-adjust JFET (AD-JEFT) and double-reduced surface fields technology is proposed. The AD-JEFT, as the conduction path of electrons from N+ source to the P-well channel, is embedded in P+ well. In the on-state, as the device is pressurized, the increase of depletion charge will reduce the effective channel width of AD-JFET. As a result, the potential barrier of the AD-JFET channel will increase rapidly, making it difficult for electrons to transfer and resulting in a reduction of the saturation current. Compared with the common LDMOS (C-LDMOS), the saturation current ( I dsat ) of the proposed LDMOS with AD-JEFT (ADJ-LDMOS) is reduced by 53.3 %. Meanwhile, the short circuit capability is improved by 110.5 %. In addition, the top P-type region of ADJ-LDMOS is divided into a higher doped P-top region and a lower doped P-top2 region, which greatly improves the blocking ability. The breakdown voltage was increased by 21.9 % without increasing the specific on-resistance ( R on,sp ).
A 1200V 4H–SiC lateral double-diffused MOSFETs (LDMOS) with embedded auto-adjust JFET (AD-JEFT) and double-reduced surface fields technology is proposed. The AD-JEFT, as the conduction path of electrons from N+ source to the P-well channel, is embedded in P+ well. In the on-state, as the device is pressurized, the increase of depletion charge will reduce the effective channel width of AD-JFET. As a result, the potential barrier of the AD-JFET channel will increase rapidly, making it difficult for electrons to transfer and resulting in a reduction of the saturation current. Compared with the common LDMOS (C-LDMOS), the saturation current ( I dsat ) of the proposed LDMOS with AD-JEFT (ADJ-LDMOS) is reduced by 53.3 %. Meanwhile, the short circuit capability is improved by 110.5 %. In addition, the top P-type region of ADJ-LDMOS is divided into a higher doped P-top region and a lower doped P-top2 region, which greatly improves the blocking ability. The breakdown voltage was increased by 21.9 % without increasing the specific on-resistance ( R on,sp ).
关键词:
quartz flexible accelerometer;heat transfer simulation model;unsteady heat conduction;temperature field
摘要:
Quartz flexible accelerometers (QFAs) are a type of temperature-sensitive sensor, whereby a change in temperature will cause the key parameters of the accelerometer to drift and cause stability errors. Due to the absence of effective methods for sensing the temperature of internal accelerometer components, existing temperature error correction approaches primarily rely on shell temperature measurements to establish correction models. Consequently, most correction methods achieve higher accuracy during the steady-state heat conduction phase of the accelerometer, whereas the correction error markedly increases during the transient heat conduction phase. To elucidate the temperature discrepancy between the QFA shell and its internal components and to support the development of a temperature error correction method for QFAs based on the internal temperature as a reference, this paper investigated the heat exchange dynamics between the interior and exterior of a QFA. A thermal conduction simulation model of the QFA was established, from which the spatiotemporal distribution patterns of the internal temperature field were derived. The results indicate that the temperature of the QFA shell changes significantly faster than that of the internal meter head in the early stage of the temperature change. The temperature gradient between the shell and the meter head first increases and then decreases, and the rate of temperature change in the upper part of the accelerometer is faster than that in the lower part. Before thermal equilibrium is reached, the temperature distribution inside the accelerometer is uneven in terms of time and space. Inside the accelerometer, the yoke iron, swing plate assembly, servo circuit, and magnetic steel assembly are the main components that exhibit differences in the internal temperature change in the QFA. When developing the temperature error correction method, it was crucial to address and mitigate the impact of temperature variations among these components. The average RMSE between the predicted temperature from the heat transfer model established in this paper and the experimental results was 0.4 °C. This indicates that the model can accurately predict the temperature variation within the QFA, thereby providing robust support for investigating the temperature behavior inside the QFA and offering essential technical foundations for enhancing the accuracy of the temperature error correction method.
摘要:
Enhancing light–matter interactions is particularly important in the field of micronano optics, which can be achieved through plasmon-induced transparency. A new type of metasurface consisting of a single layer of graphene is mainly investigated in the study. This structure is mainly composed of a graphene strip and two graphene blocks, generating plasmon-induced transparency at terahertz frequencies via weak coupling between the two bright modes. Furthermore, the time-domain finite-difference method (FDTD) and coupled-mode theory (CMT) are utilized to further explore the physical mechanism of PIT formation. By adjusting the Fermi level of graphene, the transmittance window of PIT can be effectively regulated, resulting in a reflectivity of more than 65% for this structure. Moreover, the influence of the graphene Fermi level on the slow-light effect was analyzed, and the group index was increased from 450 to 562 when the Fermi level of graphene was increased from 0.8 eV to 1.1 eV. The findings are important for the realization of multifunctional terahertz devices such as modulators and slow light.
摘要:
Compared with traditional electronic devices, spintronic devices offer the benefits of lower power consumption, faster transmission speeds, and higher integration densities. Therefore, seeking a direct and efficient method to flexibly generate spin currents in a single device, especially fully spin-polarized current (FSPC) and pure spin current (PSC), remains crucial. Inspired by this, we design a spin optoelectronic device based on the half-metal YSi 2 N 4 , and investigate its transport behavior influenced by photogalvanic effects. Remarkably, the YSi 2 N 4 spin device can generate FSPC and PSC under linearly polarized light irradiation with parallel electrode magnetic configuration (PC) or anti-parallel configuration (APC). For the YSi 2 N 4 device in PC, FSPC can be generated at any polarization angle when the photon energy is less than 2.36 eV, fulfilling the spin filtering effect. For the device in APC, PSC can be obtained across an extensive range of photon energy, which acts as an important carrier for spin transport. More interestingly, the magnetoresistance ratio of the YSi 2 N 4 device generally exceeds 90%, demonstrating excellent spin-valve effect. Our work suggests that the monolayer YSi 2 N 4 spin optoelectronic device can generate FSPC and PSC flexibly and efficiently, making it an advanced candidate for multifunctional spin devices.
期刊:
Journal of the American Ceramic Society,2025年108(8):e20565 ISSN:0002-7820
通讯作者:
Du, Y;Fabrichnaya, O
作者机构:
[Du, Yong; Yang, Lianfeng; Liu, Yuling] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Zeng, Yinping] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Peoples R China.;[Fabrichnaya, Olga] TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.;[Zhang, Ligang] Cent South Univ, Sch Mat Sci & Engn, Changsha, Peoples R China.
通讯机构:
[Du, Y ] C;[Fabrichnaya, O ] T;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;TU Bergakad Freiberg, Inst Mat Sci, D-09599 Freiberg, Germany.
摘要:
The Na2O & horbar;CaO & horbar;SiO2 ternary system, which is a very complex pseudo-ternary system, is a fundamental system widely used as glasses and glass-ceramics. Its thermodynamic description is crucial for understanding solidification and subsequent heat treatments. In this work, a thermodynamic assessment of the Na2O & horbar;CaO & horbar;SiO2 system was conducted by applying the CALPHAD method. The liquid phase in the Na2O & horbar;CaO & horbar;SiO2 system was successfully described by the two-sublattice partially ionic liquid model (Na+1,Ca+2)(P)(O-2,SiO4-4,SiO2)(Q) and two new sublattice models of (Na+1,Ca+2)(2)(Na+1,Va)(1)(Si+4)(1)(O-2)(4) and (Na+1,Ca+2)(2)(M1)(Va,Na+1)(3)(M2)(Ca+2,Na+1)(3)(M3)(Ca+2)(1)(M4)(Si+4)(6)(O-2)(18) with accurate cation distributions in their sublattices were developed to respectively describe the ternary solid solution phases beta N1C1S1 and Combeite in this work. The other ternary compounds were treated as stoichiometric ones due to their limited solid solubilities. Based on the reliable experimental data, a set of self-consistent thermodynamic parameters was obtained. The calculated isothermal sections, vertical sections, liquidus projection, and thermodynamic properties can satisfactorily reproduce the experimental data within the experimental errors. In addition, the present thermodynamic description contributes to the reliable prediction for the melting temperatures and primary crystallization phases for the Na2O & horbar;CaO & horbar;SiO2 glasses, providing valuable insights for the design of glass and glass-ceramics compositions and heat treatment processes.
摘要:
Two-dimensional (2D) second-order topological insulators (SOTIs) with corner states have recently attracted significant interest. It is fascinating to explore the coupling of corner states with additional degrees of freedom. Here, we propose that layer-polarized corner states can be induced by a perpendicular electric field in the AAstacking bilayer 2D SOTIs. Our result reveals that the transition between non-layer-polarized and layer-polarized corner states depends on the interlayer exchange symmetry, which can be controlled by the perpendicular electric field. This finding is further verified in two types of SOTIs: bilayer modified Kane-Mele model and Cn-symmetric SOTIs. In contrast to the bilayer modified Kane-Mele model, magnetic Cn-symmetric SOTIs are predicted to exhibit corner states that are not only layer polarized but also additionally spin-polarized, as exemplified by 1T-NiCl2. Based on the first-principles calculations and tight-binding (TB) model, we predict that ferromagnetic (FM) single-layer 1T-NiCl2 exhibits C3-symmetric corner states with nontrivial fractional charge in both spin channels. Notably, in the bilayer NiCl2 with antiferromagnetic (AFM) ground state, applying a perpendicular electric field drives the transition of the corner states from a spin- and layer-degenerate state to a spin- and layer-polarized state. Reversing the electric field direction simultaneously switches both the spin and layer polarizations. Finally, layer-polarized corner states are also confirmed in the nonmagnetic bilayer hexagonal SOTI. These results indicate that electrically tunable layer-polarized corner states could be realized in a variety of bilayer SOTIs and interlayer magnetic configurations. Our work offers a strategy for designing layer-polarized corner states in 2D SOTIs, which could enhance their potential applications in topological electronic devices.
摘要:
Using first-principles calculations, we systematically investigated the effects of hydrogenation and fluorination on the piezoelectric properties of single-layer honeycomb structures composed of group III–V compounds. Our findings reveal that both hydrogenation and fluorination effectively enhance piezoelectricity in these materials. For the initially flat structures lacking out-of-plane piezoelectricity, hydrogenation and fluorination induce structural distortions and out-of-plane polarizations, thereby generating out-of-plane piezoelectricity. After hydrogenation and fluorination, most group III–V compounds exhibit significantly improved vertical piezoelectricity, making them promising candidates for ultrathin piezoelectric devices operating in the d 31 mode. Notably, materials such as h-HInNH (0.59 pm / V ), h-FInNH (1.13 pm / V ), h-FInPH (0.88 pm / V ), and h-FInAsH (0.83 pm / V ) exhibit out-of-plane piezoelectric strain coefficients ( d 31 ) surpassing that of wurtzite boron nitride (0.33 pm / V ). Additionally, the in-plane piezoelectric strain coefficients ( d 11 ) of most group III–V compounds show a notable increase following hydrogenation and fluorination. These results suggest that hydrogenation and fluorination of the single-layer group III–V compounds could lead to the development of promising 2D materials for advanced piezoelectric device applications.