Highlights
Abstract +
CeRh2As2, as a recently discovered Ce-based 122-type heavy-fermion superconductor, has attracted much attention due to its non-Fermi-liquid behavior and two-phase superconductivity. The tetragonal crystal structure of CeRh2As2 maintains global centrosymmetry, which makes even-parity and odd-parity superconducting states different rather than mixed. The Ce site exhibits local inversion symmetry breaking, which results in staggered Rashba spin-orbit coupling. This may lead to the c axis field-induced transition between two superconducting phases and high critical field. Given the novel physics in CeRh2As2, including a possible quantum critical point and a spin-fluctuation-mediated superconducting pairing mechanism, the ultra-low-temperature electrical and thermal transport properties of CeRh2As2 under various magnetic fields are investigated in this work. The zero-field resistivity reveals a superconducting transition at the critical temperature Tc = 0.34 K. At a magnetic field of 1 T, a minimum resistivity appears near T0$ \approx $0.42 K, which may be due to partial gap opening caused by Fermi surface nesting, indicating that the system enters into a magnetically ordered state, which is not observed in zero field. In the temperature range from T0 to 2 K, the system exhibits non-Fermi-liquid behavior $ \rho\sim{{T}}^{0.44} $, indicating proximity to a quantum critical point. The superconducting transition is fully suppressed at 7 T, with resistivity recovering Fermi-liquid behavior at low temperature. No significant anomaly is observed in the zero-field thermal conductivity of CeRh2As2 near Tc. This absence of anomaly may be attributed to the high residual resistivity of the sample, and the reduction in carrier density during the superconducting transition and the T0 phase transition. It requires optimizing single crystal growth to reduce the effects of lattice defects or chemical disorder on thermal transport. Upon applying magnetic field, the thermal conductivity curve exhibits a small upward shift relative to its zero-field curve. At 0.15 K, thermal conductivity rises with the increase of magnetic field and is saturated at higher fields (above 5 T). In the normal state at 7 T, it is found that the electrical resistivity and thermal conductivity satisfy the Wiedemann-Franz law, indicating that both charge and heat transport are governed by the same quasiparticles, which is consistent with the Fermi-liquid behavior observed in resistivity under this field.
Abstract +
SPECIAL TOPIC—Atomic, molecular and materials properties data
EDITOR'S SUGGESTION
2025, 74 (12): 120702.
doi: 10.7498/aps.74.20250127
Abstract +
SPECIAL TOPIC—Atomic, molecular and materials properties data
EDITOR'S SUGGESTION
2025, 74 (12): 123101.
doi: 10.7498/aps.74.20250380
Abstract +
Carbon monoxide cation (CO+) plays a dominant role in some astrophysical atmosphere environments, and theoretical research on its opacity is crucial for modeling radiative transport. In this work, based on experimentally observed vibrational energy levels of the X2Σ+, A2Π, and B2Σ+ electronic states of CO+, the potential energy curves are improved and constructed using a modified Morse (MMorse) potential function, then the vibrational energy levels and spectroscopic constants are extracted. In the meantime, the internally contracted multireference configuration interaction (MRCI) method with Davison size-extensivity correction (+Q) is used to calculate the potential energy curves and transition dipole moments. The refined MMorse potential shows excellent agreement with the computed potential energy curves, while the spectroscopic constants and vibrational levels indicate strong consistency with existing theoretical and experimental data. The opacities of the CO+ molecule is computed at different temperatures under the pressure of 100 atm. The result shows that as temperature rises, the opacities of transitions in the long-wavelength range increases because of the larger population on excited electronic states at higher temperatures. All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00213.00136 .
SPECIAL TOPIC—Atomic, molecular and materials properties data
EDITOR'S SUGGESTION
2025, 74 (12): 123102.
doi: 10.7498/aps.74.20250510
Abstract +
The electronic structure of the ICl+ molecular ion is investigated by using high-level multireference configuration interaction (MRCI) method. To improve computational accuracy, Davidson corrections, spin-orbit coupling (SOC), and core-valence electron correlations effects are incorporated into the calculations. The potential energy curves (PECs) of 21 Λ-S states associated with the two lowest dissociation limits I+(1Dg)+Cl(2Pu) and I+(3Pg)+Cl(2Pu) are obtained. The dipole moments (DMs) of the 21 Λ-S states of ICl+ are systematically studied, and the variations of DMs of the identical symmetry state (22Σ+/32Σ+ and 22Π/32Π) in the avoided crossing regions are elucidated by analyzing the dominant electronic configuration. When considering the SOC effect, the Λ-S states with the same Ω components may form new avoided crossing point, making the PECs more complex. With the help of calculated SOC matrix element, the interaction between crossing states can be elucidated. Spin-orbit coupling matrix elements involving the 22Π, 32Π, 12Δ and 22Δ states are calculated. By analyzing potential energy curves of these states and the nearby electronic states, the possible predissociation channels for 22Π, 32Π, 12Δ and 22Δ states are provided. Based on the computed PECs, the spectroscopic constants of bound Λ-S and Ω states are determined. The comparison of the spectroscopic constants between Λ-S and Ω states indicates that the SOC effect has an obvious correction to the spectroscopic properties of low-lying states. Finally, the transition properties between excited states and the ground state are studied. Based on the computed transition dipole moments and Franck-Condon factors, radiative lifetimes for the low-lying vibrational levels of excited states are evaluated. All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j 00213.00140 .
SPECIAL TOPIC—Atomic, molecular and materials properties data
EDITOR'S SUGGESTION
2025, 74 (12): 125202.
doi: 10.7498/aps.74.20250301
Abstract +
SPECIAL TOPIC—Atomic, molecular and materials properties data
EDITOR'S SUGGESTION
2025, 74 (12): 127102.
doi: 10.7498/aps.74.20250352
Abstract +
Metallic materials are widely used in the industrial field due to their excellent electrical transport properties and superior thermal dissipation performance. However, experimental measurements of electrical and thermal conductivity under high-temperature and high-pressure conditions are challenging and costly. This makes numerical simulation an efficient alternative solution. In this study, we develop a computational software named TREX (TRansport at EXtremes). It is based on the Kubo-Greenwood (KG) formula combined with first-principles molecular dynamics. This software is used to calculate electrical conductivity and electronic thermal conductivity. Using magnesium and magnesium-aluminum alloy AZ31B as research subjects, we systematically investigate their electrical and thermal transport properties. The temperature and pressure are in a range of 300−1200 K and 0−50 GPa, respectively. The method involves using first-principles molecular dynamics simulations to obtain equilibrium configurations of high-temperature disordered structures. Electrical conductivity and electronic thermal conductivity are calculated using the KG formula. Lattice thermal conductivity is determined by the Slack equation. To validate the reliability of our approach, we perform comparative calculations by using the Boltzmann transport equation. The research results are cross-verified with experimental data from Sichuan University and the Aerospace Materials Test and Analysis Center. The findings demonstrate that the maximum relative error between computational and experimental results is within 20%. This confirms the accuracy of our method. Additionally, we elucidate the variation patterns of electrical and thermal conductivity in magnesium and AZ31B alloy with temperature and pressure. These patterns include the reduction in electrical conductivity due to aluminum doping, the significant enhancement of conductivity under high pressure, and the unique temperature-induced thermal conductivity enhancement in AZ31B alloy. The TREX program developed in this study and the established performance dataset provide essential tools and data support. They are useful for research on electrical and thermal transport mechanisms in metallic materials under extreme conditions, and also for engineering applications. All the data presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00213.00128.
EDITOR'S SUGGESTION
2025, 74 (12): 128101.
doi: 10.7498/aps.74.20250164
Abstract +
Strained silicon technology employing strain-relaxed SiGe virtual substrates has become pivotal factor in advancing group IV semiconductor electronics, photonic devices, silicon-based quantum computing architectures, and neuromorphic devices. Although existing approaches using Si/SiGe superlattice buffers and compositionally graded SiGe layers can produce high-quality SiGe virtual substrates, defects including threading dislocations and crosshatch patterns still limit further performance enhancement. This study demonstrates a method of fabricating fully elastically relaxed SiGe nanomembranes that effectively suppresses the formation of both threading dislocations and crosshatch patterns. The fabrication process comprises three key steps: 1) epitaxially growing Si/SiGe/Si heterostructures on silicon-on-insulator substrates via molecular beam epitaxy (MBE), 2) fabricating periodic pore arrays by using photolithography and reactive ion etching, and 3) selectively wet etching and subsequently transferring nanomembranes to Si(001) substrates. Subsequently, a Si/SiGe heterostructure is grown on the SiGe nanomembranes via MBE. The full elastic relaxation state of the SiGe nanomembranes and the fully strained state of the Si quantum well in the epitaxial Si/SiGe heterostructures are verified using Raman spectroscopy. Surface root-mean-square roughness value is 0.323 nm for the SiGe nanomembrane transferred to the silicon substrate and 0.118 nm for the epitaxial Si/SiGe heterostructure, which are demonstrated through atomic force microscopy measurements. Through electron channel contrast imaging, it is demonstrated that the Si/SiGe heterostructures grown on SiGe nanomembranes have uniform surface contrast and no detectable threading dislocations. Comparatively, the silicon substrate region exhibits high-density threading dislocations accompanied by stacking faults. Cross-sectional transmission electron microscope analysis shows atomically sharp and defect-free interfaces. This research lays a critical foundation for developing high-mobility two-dimensional electron gas systems and high-performance quantum bits.
EDITOR'S SUGGESTION
2025, 74 (12): 120701.
doi: 10.7498/aps.74.20250249
Abstract +
During flight operations, aircraft induces atmospheric disturbances in the surrounding environment through aerodynamic interactions between its geometric configuration and ambient air medium, resulting in spatially distinct density distribution characteristics that are significantly different from natural background scenario. Considering the positive correlation between atmospheric medium density and light scattering intensity, theoretical analysis shows that detecting the light scattering intensity signals in disturbed regions can map density distributions, thereby extracting the features of aircraft-induced atmospheric disturbance density fields. Based on the concept of long-range aircraft detection through atmospheric disturbance density field characterization, a novel remote sensing method for aircraft detection is proposed in this work. Specifically, a three-dimensional tomographic imaging detection mode for scattered light in an atmospheric disturbance region is designed, and a comprehensive simulation framework covering the entire process of disturbance optical signal generation, transmission, and response is constructed. The study accomplishes the following tasks: 1) the critical challenges in estimating the imaging modulation transfer function under short-exposure conditions subjected to laser pulse secondary scattering effects are resolved, and a photon scattering echo imaging simulation model for aircraft-induced disturbance density fields is established; 2) the scattering echo signal images from active light sources in disturbed density fields and the differential images obtained under disturbed background and non-disturbed background are simulated, with simulation results under varying system parameters analyzed systematically. The research demonstrates that this simulation model can be used to optimize detection system parameters, develop signal processing methods, and assess long-range detection capabilities, thus providing both theoretical foundations and technical support for advancing aircraft detection technologies based on density disturbance characteristics.
EDITOR'S SUGGESTION
2025, 74 (12): 124701.
doi: 10.7498/aps.74.20250269
Abstract +
The transition from laminar to turbulent flow is one of the main aerodynamic challenges in aircraft design and development. When the flight Mach number is sufficiently high, the aircraft surface experiences micropore effects and high-temperature gas thermochemical reactions. At present, boundary layer instability has become a more complex problem, and its mechanism is still unclear. In this study, a linear stability analysis method is developed which takes into consideration high-temperature chemical non-equilibrium process and surface micropore effect. For flight conditions at high altitude (H = 25 km) with Mach numbers 10, 15, and 20, the effects of micropore effects, chemical non-equilibrium effects, and their joint effect on flow stability are contrasted and investigated. The results show that the chemical non-equilibrium effect can contribute to the boundary layer's mode instability, while the micropore effect can restrain the second mode instability. The coexistence of the two often contributes to the instability of the second mode, because the former is heavier than the latter. The chemical non-equilibrium effect can reduce the frequency range corresponding to the second mode of pore effect inhibition, which results in the chemical non-equilibrium effect enhancing the inhibition effect of the micropore effect in the local low-frequency range and weakening its inhibition effect in the high-frequency range. This, in turn, causes a decrease in the corresponding N value variation by pore effect. Furthermore, when both effects are present, the micropore effect’s capacity to inhibit the second mode is not significantly affected by change in Mach number.
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