Highlights
Abstract +
Channel proteins act as precise molecular regulators of transmembrane transport, which is a fundamental process essential for maintaining cellular homeostasis. These proteins dynamically modulate their functional states through conformational changes, thereby forming the structural basis for complex physiological processes such as signal transduction and energy metabolism. Single-molecule fluorescence spectroscopy and single-channel patch-clamp electrophysiology represent two cornerstone techniques in modern biophysics: the former enables molecular-resolution analysis of structural dynamics, while the latter provides direct functional characterization of ion channel activity. Despite their complementary capabilities, integrating these techniques to simultaneously monitor protein conformational dynamics and functional states remains technically challenging, primarily due to the strong autofluorescence background inherent in single-molecule imaging in cellular environments. To address this limitation, we develop a spatially selective optical excitation system capable of localized illumination. By integrating tunable optical modules, we generate a dynamically adjustable excitation field on living cell membranes, achieving precise spatial registration between the excitation volume and the patch-clamp recording site. This system achieves submicron-scale alignment between the excitation zone and the micropipette contact area, enabling simultaneous electrophysiological recording and background-suppressed fluorescence detection within the clamped membrane domain. Experimental validation demonstrates that the systemcan perform single-molecule fluorescence imaging and trajectory analysis within a specified observation areas, with imaging resolution inversely related to the size of the illuminated region. Optimized optical design allows for precise excitation targeting while minimizing background illumination, thereby achieving high signal-to-noise ratio single-molecule imaging and significantly reducing photodamage. Integration with cell-attached patch-clamp configurations establishes a dual-modality platform for synchronized acquisition of single-molecule fluorescence images and single-channel recordings. The validation using mechanosensitive mPiezo1 channels confirms the system’s compatibility with single-channel recording, indicating that optical imaging induces no detectable interference to electrophysiological signal acquisition. This method overcomes longstanding challenges in the simultaneous application of single-molecule imaging and electrophysiological techniques in live-cell environments. It establishes a novel experimental framework for investigating the structure-function relationships of channel proteins and membrane-related molecular machines through spatially coordinated optoelectronic measurements on live-cell membranes, which has broad applicability in molecular biophysics and transmembrane transport mechanism research.
SPECIAL TOPIC—Order tuning in disordered alloys
EDITOR'S SUGGESTION
2025, 74 (13): 136101.
doi: 10.7498/aps.74.20250585
Abstract +
SPECIAL TOPIC—Order tuning in disordered alloys
EDITOR'S SUGGESTION
2025, 74 (13): 136401.
doi: 10.7498/aps.74.20250392
Abstract +
This study aims to establish the intrinsic link between the high-temperature rheological behavior and kinetic relaxation characteristics of La-based metallic glasses. By conducting dynamic mechanical analysis and high-temperature tensile strain-rate jump experiments on three La-based metallic glasses with significant β relaxation, and combining the findings within the free volume theory framework, their high-temperature rheological properties are investigated systematically. The results show that the steady-state flow stress and activation volume evolution trend are consistent within the normalized temperature range. The average activation energy for high-temperature rheology aligns with the activation energy range of α relaxation, confirming the strong association between rheological behavior and α relaxation. The activation energy for β relaxation shows an opposite trend, indicating that it may precede α relaxation. A dynamic competition between defect annihilation and generation governs the rheological behavior, and kinetic parameters reveal the temperature and strain-rate sensitivity of metallic glasses. This study lays a theoretical foundation for optimizing the high-temperature mechanical properties of La-based metallic glasses and also provides new insights into understanding the coupling relationship between multi-scale relaxation behavior and rheological mechanisms in metallic glasses.
SPECIAL TOPIC—Order tuning in disordered alloys
EDITOR'S SUGGESTION
2025, 74 (13): 138102.
doi: 10.7498/aps.74.20250518
Abstract +
High-entropy alloy (HEA) microfibers exhibit promising prospects in microscale high-tech applications due to their exceptional mechanical properties and stability. However, the strength-plasticity tradeoff largely hinders their further industrial applications. Heat treatment can optimize the mechanical properties of HEA microfibers. However, the traditional heat treatment (CHT) faces challenges in accurately adjusting the microstructures in a short period of time, while also being prone to grain coarsening, which can affect performance. In this study, an electric current treatment (ECT) technique is used to finely modulate the properties of cold-drawn CoCrFeNi high-entropy alloy microfibers on a microscale (~70 μm in diameter), the effects of thermal and athermal effects during ECT on microstructure and mechanical properties are systematically investigated through electron back scatter diffraction, transmission electron microscopy, and synchrotron radiation. A model of recrystallization, nucleation and growth of HEA microfibers is established. Compared with CHT, the synergistic effects of electron wind force and Joule heating during ECT significantly accelerate recrystallization kinetics, yielding finer and more homogeneous grains with a great decrease in dislocation density, and finally lead to better mechanical properties. The ECT-processed HEA microfibers achieve a yield strength in a range from 400 to 2033 MPa and a tensile elongation reaching 53%, which are much higher than those of CHT samples. These results demonstrate that the ECT is effective for optimizing the microstructure and properties of HEA microfibers, and can also provide both a theoretical foundation and technical guidance for fabricating high-performance metallic microfibers.
Abstract +
Rare-earth elements possess unique atomic structures characterized by multiple unpaired 4f orbital electrons in inner shells, high atomic magnetic moments, and strong spin-orbit coupling. These attributes endow them with rich electronic energy levels, enabling them to form compounds with different valence states and coordination environments. Consequently, rare-earth materials typically exhibit excellent magnetic properties and complex magnetic domain structures, making them critical for the development of high-tech industries. The intricate magnetic configurations, different types of magnetic coupling, and direct/indirect magnetic exchange interactions in these materials not only facilitate the development of novel functional devices but also pose significant challenges to fundamental research. With the rapid advancement of data mining techniques, the emergence of big data and artificial intelligence provides researchers with a new method to efficiently analyze vast experimental and computational datasets, thereby accelerating the exploration and development of rare-earth magnetic materials. This work focuses on rare-earth permanent magnetic materials, rare-earth magnetocaloric materials, and rare-earth magnetostrictive materials, detailing the application progress of data mining techniques in property prediction, composition and process optimization, and microstructural analysis. This work also delves into the current challenges and future trends, aiming to provide a theoretical foundation for deepening the integration of data mining technologies with rare-earth magnetic material research.
EDITOR'S SUGGESTION
2025, 74 (13): 137202.
doi: 10.7498/aps.74.20250295
Abstract +
Janus transition metal dichalcogenide monolayers, characterized by antisymmetric crystal structures and unique physical properties, show great potential applications in micro/nano-electronic devices and thermoelectrics. In this work, the strain-tuned phonon thermal transport and thermoelectric performance of six Janus transition metal dichalcogenide monolayers are systematically investigated by first-principles calculations. This study focuses on monolayers of PtSSe and PtTeSe with a 1T-phase crystal structure, as well as monolayers of MoSSe, MoTeSe, WSSe, and WTeSe with a 1H-phase crystal structure. For all these monolayers, first-principles calculations are performed using the open-source software Quantum ESPRESSO. The lattice thermal conductivity is obtained based on lattice dynamics and iterative solutions of the Boltzmann transport equation. The thermal conductivities of PtSSe, MoSSe, and WSSe monolayers are generally higher than those of PtTeSe, MoTeSe, and WTeSe. Acoustic phonons are responsible for the majority of thermal transport, contributing over 95%. Under unstrained conditions, monolayer PtSSe demonstrates a superior thermal conductivity of 104 W·m–1·K–1, making it advantageous for thermal management applications in electronic devices. Under tensile strain, the thermal conductivities of PtSSe, MoSSe, and WSSe monolayers exhibit a monotonic decrease trend; however, for PtTeSe, MoTeSe, and WTeSe monolayers, their thermal conductivities initially show an increase trend, followed by a subsequent decrease trend. Under a 10% tensile strain, the thermal conductivities of these six Janus monolayers all demonstrate a reduction exceeding 60%. Furthermore, this work provides a comprehensive analysis of the influences of strain on specific heat capacity, phonon group velocity, and phonon lifetime. The phonon mode-level analysis and cross-calculated thermal conductivity (with specific heat capacity, phonon group velocity, and phonon lifetime replaced by values under different strain conditions) reveal that phonon lifetime is the dominant factor governing thermal conductivity under strain. For electrical transport properties, calculations are performed using the Boltzmann transport equation based on deformation potential theory. At room temperature, the thermoelectric figure of merit (ZT) for PtTeSe is 0.91 without strain, which can be improved to 1.31 under 10% tensile strain. The ZT value reaches as high as 3.96 for p-type PtTeSe and 2.38 for n-type PtTeSe at 700 K, indicating that the PtTeSe monolayer is a highly promising thermoelectric material. Strain-induced enhancement in the thermoelectric performance of PtTeSe is facilitated by reducing lattice thermal conductivity and reconfigurating the band structure. This work demonstrates that strain engineering is an effective strategy for adjusting the thermal transport and thermoelectric properties of Janus transition metal dichalcogenide monolayers.
Abstract +
In extreme radiation environments, such as space nuclear reactor systems, deep-space probe power modules, and launch vehicle propulsion systems, high-voltage and high-power devices demonstrate significant practical value. Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) possess advantages including high breakdown voltage, thermal stability, and low on-state resistance, enabling further improvements in aerospace power supply efficiency. Therefore, research on radiation effects and radiation-hardening techniques for SiC power MOSFETs has rapidly emerged as a critical focus in the industry. Firstly, this paper reviews the developmental evolution of SiC power MOSFETs, analyzes the necessity of transitioning from planar gate to trench-gate architectures, and provides future prospects for advanced SiC power MOSFET technologies. Secondly, it systematically compiles current research achievements in single event burnout (SEB) and single event gate rupture (SEGR) caused by heavy ion irradiation in SiC power MOSFETs. Finally, based on a mechanistic analysis of radiation-induced single event damage in SiC power MOSFETs, this study summarizes recent progress of radiation-hardening technologies, aiming to provide valuable ideas for understanding radiation induced failure mechanisms and enhancing the radiation tolerance of SiC power MOSFETs.
Abstract +
We numerically solved the time-dependent Schrödinger equation (TDSE) for a hydrogen atom interacting with intense near-infrared laser fields to investigate the mechanism of below-threshold high-harmonic generation (HHG). The primary focus was on understanding the spectral features, particularly resonant structures, arising in the fifth harmonic region under specific driving conditions. Our simulations utilized a laser wavelength of 608 nm. At this wavelength, hydrogen atoms can resonantly absorb five photons, promoting electrons from the ground stateWe numerically solved the time-dependent Schrödinger equation (TDSE) for a hydrogen atom interacting with intense near-infrared laser fields to investigate the mechanism of below-threshold high-harmonic generation (HHG). The primary focus was on understanding the spectral features, particularly resonant structures, arising in the fifth harmonic region under specific driving conditions. Our simulations utilized a laser wavelength of 608 nm. At this wavelength, hydrogen atoms can resonantly absorb five photons, promoting electrons from the ground state $\left|1{\mathrm{s}}\right\rangle$ to the excited state $\left|2{\mathrm{p}}\right\rangle$. Concurrently, the atom can absorb additional photons leading to ionization. Crucially, due to the AC Stark shift induced by the intense laser field (laser dressing), some laser-dressed continuum states $\left|{\mathrm{c}}\right\rangle$ become energetically degenerate with the laser-dressed $\left|2{\mathrm{p}}\right\rangle$ state. High-harmonic radiation at the fifth harmonic frequency can then be emitted via two distinct quantum paths: 1) Bound-bound recombination: Direct recombination from the laser-dressed $\left|2{\mathrm{p}}\right\rangle$ state back to the ground state $\left|1{\mathrm{s}}\right\rangle$. 2) Continuum-bound recombination: recombination from the laser-dressed continuum states $\left|{\mathrm{c}}\right\rangle$ (reached via ionization) back to $\left|1{\mathrm{s}}\right\rangle$. Both pathways emit photons of identical energy corresponding to the fifth harmonic. Our important finding is that there is significant quantum interference between these two recombination channels. This interference is manifested in the spectrum as an asymmetric Fano lineshape of the fifth harmonic intensity profile. Furthermore, we demonstrate that the shape of this Fano resonance exhibits strong and controllable dependence on the intensity of the driving laser field. This study provides clear evidence that Fano quantum interference, typically associated with multi-electron correlations or autoionizing states in complex systems, can emerge in the fundamental single-electron hydrogen atom system under the condition of intense laser field. The interference arises directly from the coherent superposition of the bound-bound and continuum-bound recombination pathways caused by laser-induced degeneracy. Importantly, by adjusting the laser intensity the spectral profile of the Fano resonance can be actively manipulated, providing a novel method for coherently controlling the harmonic emission in simple atomic systems.
Abstract +
In recent years, the design and development of new high-performance alloys based on first principles have received extensive attention. However, there are few reports on the structural design and thermodynamic properties of Cu-Zr alloys at nanoscale. In this work, based on the crystal structure characteristics of CuZr2, 12 kinds of Cr-doped CuZr2 structures are designed and optimized by the method of Cr atom doping through the first-principle calculation based on the density functional theory, and 6 kinds of mechanically and dynamically stable doped structure models are found. By calculating the electronic structure, elastic properties and hardness of the CuZr2 and its dynamically stable Cr-doped structure, it is found that the studied objects have all energy bands that pass through the Fermi energy level and are metallic. The main contributors to the metallic properties of the CuZr2 are the p and d orbital electrons of Zr, while the main contributors to the metallic properties of the 6 dynamically stable Cr-doped CuZr2 structures are the p and d orbital electrons of Cr and Zr. Meanwhile, CuZr2 has symmetrically distributed spin electrons, which do not show magnetism externally. However, the doping of Cr atoms increases the elemental species of the matrix. In addition to the difference of spin electrons brought by the d-orbital electrons of Cr atoms, the doped Cr atoms destroy the symmetrical distribution of electrons with different spin directions in the p- and d-orbitals of Zr atoms in the matrix, so that the designed 6 dynamically stable Cr-doped CuZr2 structures exhibit ferromagnetic properties with magnetic moments ranging from 0.303μB to 5.243μB. In addition, it is found that Cr atoms can improve the mechanical properties of CuZr2. When the Cr atom is used to replace the Zr atom in the matrix, the elastic modulus and hardness of the material can be improved, and when the Cr atom is used to replace the Cu atom in the matrix, the machining properties of the material can be improved due to the reduction of hardness. The datasets presented in this work, including the band structure, density of states, and phonon dispersion frequency, are available from https://www.doi.org/10.57760/sciencedb.j00213.00122 .
EDITOR'S SUGGESTION
2025, 74 (13): 134202.
doi: 10.7498/aps.74.20250418
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