Accepted
, , Received Date: 2025-08-30
Abstract +
Two-dimensional (2D) magnetic materials refer to nanomaterials with an extremely thin thickness that can maintain long-range magnetic order. These materials exhibit significant magnetic anisotropy, and due to the quantum confinement effect and high specific surface area, their electronic band structures and surface states undergo remarkable changes. As a result, they possess rich and tunable magnetic properties, showing great application potential in the field of spintronics. The 2D magnetic materials include layered materials, where layers are stacked by weak van der Waals forces, and non-layered materials, which are bonded via chemical bonds in all three-dimensional directions. Currently, most of researches focus on 2D layered materials, but their Curie temperatures are generally much lower than room temperature, and they are always unstable when exposed to air. In contrast, the non-layered structure enhances the structural stability of the materials, and the abundant surface dangling bonds increase the possibility of modifying their physical properties. Such materials are attracting increasing attention, and significant progress has been made in their synthesis and applications. This review first systematically summarizes various preparation methods for 2D non-layered magnetic materials, including but not limited to ultrasound-assisted exfoliation, molecular beam epitaxy, and chemical vapor deposition. Meanwhile, it systematically reviews the 2D non-layered intrinsic magnetic materials obtained in various types of materials in the past five years, as well as a series of novel physical phenomena emerging under the ultrathin limit, such as thickness-dependent magnetic reconstruction dominated by quantum confinement effects and planar topological spin textures induced by 2D structures. Furthermore, it also discusses the critical role played by theoretical calculations in predicting new materials through high-throughput screening, revealing microscopic mechanisms by analyzing magnetic interactions, as well as some important methods of modifying magnetism. Finally, from the perspectives of material preparation, physical mechanisms, device fabrication, and theoretical calculations, the current challenges in the field are summarized, and the application potential and development directions of 2D non-layered magnetic materials in spintronic devices are prospected. This review aims to provide comprehensive references and scientific perspective for researchers engaged in this field, thereby promoting further exploration of the novel magnetic properties of 2D non-layered magnetic materials and their applications in spintronic devices.
, , Received Date: 2025-08-28
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Polarization detection is a fundamental way to obtain the vectorial nature of light, supporting advanced technologies in the fields of optical communication, intelligent sensing, and biosensing. Two-dimensional van der Waals materials have become a promising platform for high-performance polarization-sensitive photodetectors due to their inherent anisotropy and tunable electronic properties. Nevertheless, their intrinsically weak light absorption and limited photoresponse efficiency remain major bottlenecks. Plasmonic nanostructures, which can achieve strong localized field confinement and manipulation on a nanoscale, provide an effective strategy to overcome these limitations and substantially improve device performance. In this review, we systematically summarize the coupling mechanisms between plasmonic architectures and vdW materials, highlighting near-field enhancement, plasmon-induced hot-carrier generation, and mode-selective polarization coupling as key physical processes for enhancing photocarrier generation and polarization extinction. Representative devices including metallic gratings, hybrid nanoantennas, and chiral metasurfaces are compared in terms of responsivity, detection speed, operating bandwidth, and polarization extinction ratio, revealing consistent improvements of one to two orders of magnitude over bare vdW devices. We further survey emerging applications in the fields of high-speed polarization-encoded optical communication, on-chip optical computing and information processing, and bioinspired vision and image recognition systems, where plasmonic-vdW hybrid detectors demonstrate unique advantages in miniaturization and energy efficiency. Finally, we discuss current challenges such as large-scale fabrication of uniform plasmonic arrays, spectral bandwidth broadening, and seamless integration with complementary photonic circuits, and outline future opportunities for next-generation polarization-resolved optoelectronic platforms.
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Abstract +
Electron-ion collision is one of the fundamental processes in atomic and molecular physics, and the study of this process can provide insight into the mechanism of electron-atom/ion interaction. It has important applications in plasma physics and astrophysics. Accurate electron-impact cross-sections are important in plasma modeling. In generally, total EISI cross-sections consists of the direct ionization (DI) and the indirect ionization processes, with the latter further divided into excitation autoionization (EA), resonant excitation double auto-ionization (REDA) and resonant excitation auto- double ionization (READI) processes. In this work, the electron-impact single ionization (EISI) crosssections for the ground state [Kr]4d105s24f13 of W13+ ions are calculated in detail by using the level-to-level distorted-wave (LLDW) method, which mainly includes the contributions of direct ionization (DI) and excited auto-ionization (EA) cross-sections to the EISI cross-sections. Our computational results demonstrate that when configuration interaction are incorporated, the calculated values show excellent agreement with experimental data for electron impact energies exceeding 500 eV. However, significant discrepancies persist near the ionization threshold. we have confirmed that these discrepancies primarily originate from the presence of long-lived metastable ions. To achieve better agreement with experimental observations, we further calculated EISI cross-sections for 71 energy levels of the metastable state 4 d10 5 s2 4 f12 5p with lifetimes greater than 1.5×10-5s. The total EISI cross-sections of these 71 energy levels were obtained by theoretical fitting and compared with the experimental results by Schury et al. (Figure), and it was found that our results were in good agreement with the experimental results of Schury et al. after considering the contribution of long-lived metastable.
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Abstract +
The lower friction coefficient and better mechanical properties of palladium (Pd) alloys make them potentially advantageous for use in high-precision instruments and devices that require long-term stable performance. However, due to the high cost of raw materials and experimental expenses, there is a lack of fundamental data, hindering the design of high-performance Pd alloys. Therefore, in this study, first-principles calculations were used to determine the lattice constant and elastic modulus of Pd. A dilute solid solution model was established for Pd alloys with 33 elements, including Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and others. The mixing enthalpy, elastic constants, and elastic modulus were calculated. The results show that, except for Mn, Fe, Co, Ni, Ru, Rh, Os, and Ir, all other alloying elements can form solid solutions with Pd. Alloying elements from both sides of the periodic table enhance the ductility of Pd solid solutions, with La, Ag, and Zn having the most significant effects, while Cu and Hf reduce the ductility of Pd. Differential charge density analysis indicates that the electron cloud formed after doping with Ag is spherically distributed, which improves ductility. After doping with Hf, the degree of delocalization around the atoms is maximized, suggesting a strong ionic bond between Hf and Pd, leading to a higher hardness of Pd31Hf.
The datasets presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00213.00186(https://www.scidb.cn/s/uqMzye)
The datasets presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00213.00186(https://www.scidb.cn/s/uqMzye)
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Terahertz (THz) polarization converters are essential components for advancing THz applications in imaging, sensing, and high-speed communications. However, achieving both broad bandwidth and high conversion efficiency remains a significant challenge. In this work, we propose, fabricate, and experimentally validate a transmissive linear polarization converter (TTPC) operating in the terahertz band, utilizing a bilayer metallic metamaterial structure. The device consists of a top-layer metasurface with a square patch and split-ring resonators and a bottom-layer metallic grating, separated by a polyimide substrate. Through full-wave electromagnetic simulations and surface current analysis, we reveal that the high-performance broadband polarization conversion arises from the synergistic interaction among three distinct resonance modes. Stokes parameter analysis further confirms that the polarization rotation angle remains stable at approximately 90° with near-linear output across the operational band. Experimental characterization using a terahertz time-domain spectroscopy (THz-TDS) system demonstrates that the device achieves a polarization conversion ratio (PCR) exceeding 92% over a broad frequency range of 0.53–1.77 THz, corresponding to a relative bandwidth of 108%. The measured insertion loss varies between 5.5 dB and 12 dB within the operating band, which is attributed to ohmic loss, dielectric absorption, and resonant energy dissipation. Despite these losses, the converter maintains high polarization purity and practical utility. With a compact and fabrication-friendly architecture, the proposed TTPC offers a viable route toward high-performance, broadband polarization control in terahertz systems, paving the way for its integration into next-generation THz communication and imaging devices.
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Abstract +
In order to distinguish the interaction responses between unsteady thermal waves and thermal diffusion in graphene, the relaxation time of the heat flux vector τq and the relaxation time of the temperature gradient τT are introduced based on the Fourier's law, and a two-phase relaxation theoretical model is established. Parameter B describing ratio of the two phase relaxation times is employed to reveal the influencing rules of the interaction between thermal waves and thermal diffusion, and to investigate the regulatory mechanism of heat transport modes. When B approaches zero, the thermal wave effect dominates the heat transfer. When B approaches 0.5, the thermal diffusion characteristics are significant. When B is between zero and 0.5, both of them jointly dominate heat transfer, and the interaction between the two is of great significance. The results uncover the rules of thermal diffusion induced wave attenuation and thermal wave promoted thermal diffusion. They exhibit strong coupling characteristics. The unique contribution of third-order partial derivatives to local thermal wave disturbances is also revealed. A molecular dynamics model of short-pulse thermal shock for zigzag graphene is developed to unveil the coupling behaviors of thermal waves and thermal diffusion. The calculation parameters of two-phase relaxation theoretical model are calibrated. The main findings are presented in the figure below. The black, red, and yellow lines correspond to the in-plane longitudinal vibration, in-plane transverse vibration, and out-of-plane transverse vibration of carbon atoms, respectively. The solid lines denote elastic waves, while the dashed lines represent the second sound. The temperature field following the second sound is the outcome of the combined action of thermal waves and thermal diffusion. It merits attention that except for speed of the out-of-plane thermal wave is higher than that of the out-of-plane transverse elastic wave, speeds of the other two thermal waves are both lower than their elastic wave velocities.
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Abstract +
Inorganic cesium halide perovskites (CsPbX3, X=I,Br) are promising candidates as the light-harvesting materials of new-generation photovoltaic devices owing to their intrinsic advantages, such as the high thermal stability, excellent optoelectronic properties, and facile solution fabrication process. In particular, CsPbI2Br perovskite which balances the light-harvesting ability and phase stability has attracted ever-increasing attention in the field of the single junction, the tandem, and the semitransparent photovoltaic devices. In the past several years, inorganic CsPbI2Br perovskite solar cells (PSCs) have achieved great progress in both the power conversion efficiency and the stability through versatile device engineering. Nevertheless, the inferior buried interface derived from the uncontrollable up-to-bottom perovskite crystallization process leads to the serious charge recombination and energy loss within CsPbI2Br PSCs, which considerably hinders the further development and practical deployment of CsPbI2Br PSCs. This highlights the necessity of developing facile but effective strategy to modify buried interface towards achieving superior cell performance. In this work, we report a facile additive strategy to in situ modify the buried interface of CsPbI2Br PSCs through forming a dipolar interlayer. The polar 4-mercaptophenylboronic acid (4-MPBA) additive is directly added into CsPbI2Br precursor solution. 4-MPBA molecules can't incorporate into the crystal lattice of CsPbI2Br perovskite due to its large size. Therefore, 4-MPBA molecules are excluded from CsPbI2Br perovskite crystal and pushed downwards the buried interface of TiO2 electron-transport-layer and CsPbI2Br perovskite film during the perovskite crystallization process. Because of the strong interaction between the -B(OH)2 group of 4-MPBA molecule and TiO2, 4-MPBA molecules tend to accumulate at the buried interface between CsPbI2Br perovskite and TiO2 layer and form a dipolar interlayer. Scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy measurements clearly demonstrate that the formation of 4-MPBA interlayer greatly enhance the interface contact, improve the interfacial energy level structure, and passivate the interface defects, which effectively suppresses the charge recombination and promotes the charge collection within the cell. As a result, the assembled carbon-based CsPbI2Br PSC without hole-transport layer delivers a power conversion efficiency of 14.83%, which is increased by 26% compared to the efficiency of the cell without 4-MPBA interlayer. Moreover, the cell without any encapsulation retains ~90% of the original efficiency after 960 h of aging in ambient air, suggesting a superior long-term stability. Therefore, this work highlights a facile strategy to in situ modify the buried interface for effectively enhancing the photovoltaic performance of inorganic perovskite solar cells.
, , Received Date: 2025-07-29
Abstract +
To meet the urgent demand for high-performance photodetectors in emerging solar-blind ultraviolet communication applications, this study systematically designs and implements a fully transparent β-Ga2O3 solar-blind photodetector based on a back-illumination architecture. The device is fabricated using RF magnetron sputtering to epitaxially grow high-quality β-Ga2O3 films (~300 nm in thickness, ~4.98±0.05 eV in bandgap) on double-polished sapphire substrates, with indium tin oxide (ITO) interdigitated electrodes forming efficient quasi-Ohmic contacts with n-type Ga2O3. The core advantage of this design lies in exploiting the high deep-UV transmittance of double-polished sapphire substrates, enabling incident photons to completely bypass the UV-absorbing ITO electrodes and eliminate photon loss caused by electrode shadowing effects in traditional front-illumination configurations. Consequently, the device demonstrates exceptional optoelectronic performance: a maximum responsivity of 0.46 A/W corresponding to an external quantum efficiency of 222.4%, an outstanding UV/visible rejection ratio of 1.2×104, a minimum noise equivalent power of 1.52 pW/Hz1/2, and a peak specific detectivity of 1.39×1011 Jones, with fast response times of 24 μs (rise) and 1.24 ms (decay). Building on this high-performance detector platform, we further explore its multifunctional application potential by constructing a polarization detection system that utilizes the intrinsic lattice anisotropy of monoclinic β-Ga2O3, and successfully demonstrating a non-line-of-sight (NLOS) UV communication system that validates high-fidelity information transmission in complex scattering channels. This work provides effective physical insights and experimental basis for developing next-generation Ga2O3-based optoelectronic devices with integrated high sensitivity, polarization resolution, and NLOS communication capabilities, showing promising applications in secure communications and polarization imaging.
, , Received Date: 2025-08-25
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, , Received Date: 2025-08-14
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This paper provides a comprehensive review of recent advances in high-performance photodetectors based on two-dimensional materials and in-sensor computing for intelligent image processing, aiming to address the challenges of the “memory wall” and “power wall” caused by the separation of sensing, storage, and computing in traditional image sensors. Traditional image processing relies on the von Neumann architecture, where a large volume of raw data generated at the sensing end must be transmitted to independent computing units or cloud platforms for processing, leading to high energy consumption, significant latency, bandwidth burden, and security risks. Owing to their atomic thickness, high carrier mobility, weak short-channel effects, and tunable optoelectronic properties, two-dimensional (2D) materials provide an ideal physical foundation for achieving function integration of perception and computation. This paper discusses the topic from three perspectives: optical signal perception, image preprocessing, and advanced image processing. In terms of optical signal perception, 2D materials and their heterostructures exhibit ultrahigh responsivity, broadband operation, and fast response in light-intensity detection, enable miniaturized spectrometers through bandgap modulation and computational spectroscopy, and achieve compact, full-polarization analysis via twisted layers and metasurface structures. In image preprocessing, 2D material devices can perform convolution and feature extraction at the sensing end through linear photoresponse, suppress noise and extend dynamic range via superlinear and sublinear responses, and mimic biological visual adaptation in spectral and polarization domains to enhance image quality and robustness. In advanced image processing, the tunable photoresponse and memristive characteristics of 2D materials enable sensor-level integration of sensing, storage, and computation, This allows for the realization of matrix-vector multiplication and convolution operations within convolutional neural networks, significantly reducing power consumption and improving efficiency. Meanwhile, by implementing spike-rate and temporal encoding of optical signals in spiking neural networks, 2D material devices can achieve event-driven image recognition and classification under low-power and low-latency conditions. Furthermore, this paper highlights the challenges faced by 2D material image sensors, including scalable fabrication, heterogeneous integration with silicon technology, array- and circuit-level optimization, environmental stability and encapsulation, and system-level implementation, while envisioning their broad application prospects in intelligent imaging, wearable electronics, autonomous driving, and biomedical diagnostics. It is concluded that with the joint progress in materials science, device engineering, and artificial intelligence, 2D materials are expected to drive the development of next-generation low-power, high-performance, intelligent image processing platforms, and to become an essential foundation for future information perception and processing technologies.
, , Received Date: 2025-06-20
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The increasing demands for high-speed imaging, aerospace, and optical communication have driven in-depth research on broadband photodetectors with high sensitivity and fast response. Two-dimensional (2D) materials have atomic-scale thickness, tunable bandgaps, and excellent carrier transport properties, making them ideal candidates for next-generation optoelectronics. However, their limited light absorption and intrinsic recombination losses remain key challenges. This paper provides an overview of recent progress of 2D-material-based broadband photodetectors. First, the fundamental optoelectronic properties of 2D materials, including bandgap modulation, carrier dynamics, and light–matter interactions, are discussed to clarify their broadband detection potential. Representative material systems, such as narrow-band gap semiconductors, 2D topological materials, and perovskites, are summarized, showing the detection ability from the ultraviolet to the mid-infrared regions. To overcome intrinsic limitations, four optimization strategies are highlighted: heterostructure engineering for efficient charge separation and extended spectral response; defect engineering to introduce mid-gap states and enhance sub-bandgap absorption; optical field enhancement through plasmonic nanostructures and optical cavities to improve responsivity; strain engineering for reversible band structure tuning, particularly suited for flexible devices. These strategies have achieved significant improvements in responsivity, detectivity, and bandwidth, with some devices implementing ultrabroadband detection and multifunctionality. In summary, 2D materials and their hybrids have shown great potential in broadband photodetection, with progress made in material innovation and device architecture optimization. The reviewed strategies—heterostructure integration, defect modulation, optical field enhancement, and strain engineering—collectively demonstrate the different ways of overcoming intrinsic limitations and improving device performance. Looking ahead to the future, the reasonable combination of these methods is expected to further expand the detection window, improve sensitivity, and achieve multifunctional operations, thereby paving the way for the multifunctional applications of the next-generation broadband photodetectors in imaging, sensing, and optoelectronic systems
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This study investigates the magnetocaloric effect-based green magnetic refrigeration technology, with a focus on Ni-Mn-Ga Heusler alloys as promising magnetic refrigerant candidates. To elucidate the role of Mn-rich composition in regulating the magnetic and magnetocaloric properties, a multi-scale computational approach integrating first-principles calculations and Monte Carlo simulations was adopted. This methodology enables a detailed analysis of how Mn atoms occupying Ni versus Ga sites influence the alloy’s microstructure, atomic magnetic moments, exchange interactions, and macroscopic magnetocaloric response. The results demonstrate that Mn site occupancy critically governs the magnetic performance: occupation of Ni sites reduces the total magnetic moment and Curie temperature, thereby diminishing the magnetic entropy change; in contrast, Mn occupying Ga sites markedly enhances both the total magnetic moment and the magnetic entropy change. Notably, the Ni8Mn7Ga1 alloy achieves a maximum magnetic entropy change of 2.32 J·kg-1·K-1 under a 2 T magnetic field, substantially surpassing that of the stoichiometric Ni8Mn4Ga4 alloy. Further electronic structure analysis reveals that Mn content variation modulates the density of states near the Fermi level, optimizes orbital hybridization and ferromagnetic exchange interactions, and consequently tailors the magnetic phase transition behavior. Critical exponent analysis confirms that the magnetic interactions are long-range in nature and tend toward mean-field behavior with compositional changes. By establishing a clear “composition-structure-magnetism-magnetocaloric performance” relationship at the atomic scale, this work provides theoretical foundations for designing high-performance, low-hysteresis magnetic refrigeration materials.
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For terahertz systems where reflected signals carry effective information, such as terahertz time-domain reflection systems and full-duplex communication systems, existing nonreciprocal terahertz devices often treat reflected signals as interference and suppress them during isolation. This makes them incompatible with the requirements of such systems for isolating incident signals while directionally extracting and detecting reflected signals. To address this limitation, this study innovatively proposes a terahertz isolator based on a magneto-optical selection–multiport architecture. The device converts linearly polarized light into a specific circular polarization state through orthogonal double gratings and, combined with the magneto-optical selectivity of InSb material, constructs a nonreciprocal transmission path. Furthermore, the magneto-optical regulation mechanism innovatively incorporates branch waveguides with multiple ports and the characteristic of regulating terahertz transmission paths, simultaneously achieving isolation of incident/reflected signals and directional extraction of reflected signals. By simulating the influence of structural dimensions and external environmental conditions on the nonreciprocal characteristics of the device, it is found that under a temperature of 250 K and a magnetic field of 0.3 T, with the structural parameters set as branch length of 170 μm, center-to-center spacings of adjacent branches of 125 μm, 125 μm, 120 μm, and 120 μm, InSb layer thickness of 5 μm, grating layer thickness of 50 μm, and substrate layer thickness of 20 μm, the device achieves a high isolation of 63.12 dB at 0.73 THz. Additionally, at 0.78 THz, the bidirectional transmission efficiency reaches 36.31%, with a 3 dB bandwidth of 0.25 THz. This device offers advantages such as high isolation, low operating magnetic field strength, and integration of dual functions. It reduces interference from incident signals on reflected signals, simplifies subsequent processing steps such as noise reduction and localization of effective reflected signals, and enhances the system's detection performance for weak signals. This provides essential support for expanding terahertz applications to more fields, including non-destructive testing and communication.
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Magnetic refrigeration technology, featuring environmental friendliness, energy efficiency and high performance, is recognized as a next-generation refrigeration technology with the potential to replace gas compression refrigeration technology. However, current magnetic refrigeration materials typically exhibit an excessively narrow phase transition temperature range (≤ 10 K), necessitating the stacking of materials with multiple compositions to meet the practical refrigeration temperature span. In this study, the typical La(Fe, Si)13-based magnetic refrigeration material was selected, and an innovative gradient laser powder bed fusion technology was adopted to 3D-print La0.70Ce0.30Fe11.65-xMnxSi1.35 alloys with horizontal compositional gradients (where the Mn content varies continuously from 0 to 0.64). Systematic characterization of their microstructure, magnetic properties, and magnetocaloric effect indicates that this technology enables controllable gradient distribution of compositions along the powder bed plane and high-throughput preparation, thereby achieving a continuous variation of the Curie temperature of the gradient alloy over a wide temperature range from 134 K to 174 K. With the increase of Mn content, the phase transition of the alloy gradually transforms from a weak first-order phase transition to a second-order phase transition, and the peak shape of the magnetic entropy change curve shifts from "sharp and high" to "broad and flat". The full width at half maximum of the temperature range expands to 83.3 K, allowing the gradient alloy to consistently maintain a high refrigeration capacity (RC ~130 J kg-1， 3 T). This study breaks through the bottlenecks of traditional material preparation and performance via gradient additive manufacturing, providing a novel technical pathway for the high-throughput preparation and performance optimization of magnetic refrigeration materials.
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