This study introduces a novel two-dimensional inorganic graphenylenelike monolayer, scandium nitride (IGP-ScN), and examines its stability and functional properties using density functional theory (DFT) simulations. Phonon dispersion analysis and ab initio molecular dynamics in the NVT ensemble (300–900 K) confirm both dynamical and thermal robustness. At the PBE level, electronic structure calculations indicate an indirect band gap at $M\to \mathrm{\Gamma }$. The Bethe-Salpeter equation solution reveals an indirect excitonic ground state and an optical gap at 1.96 eV, indicating a large exciton binding energy (646 meV) and a pronounced excitonic red shift. The monolayer satisfies the Born-Huang stability criteria and demonstrates an essentially isotropic in-plane elastic response, with a Young's modulus of approximately 52 N/m, a shear modulus of approximately 17 N/m, and a Poisson's ratio of approximately 0.51. The lattice thermal conductivity is low, ranging from 0.09 W/(m K) at 300 K to 0.03 W/(m K) at 900 K. Although the undoped structure has low figure-of-merit (zT) values, doping at elevated temperatures can improve performance, with electron doping more effective than hole doping. Power conversion efficiency (PCE) results show Shockley-Queisser limit efficiencies of $10.58\%$ at the independent particle approximation level and $23.19\%$ at the Bethe-Salpeter level, with the latter enhanced by the excitonic redshift, which reduces the optical band gap from 2.42 to 1.96 eV. These findings may encourage further investigation of new III–V semiconductors and novel inorganic lattices by both experimental and theoretical researchers.

We report the magnetic properties of a ${\mathrm{Yb}}^{3+}$-based hyperkagome compound ${\mathrm{Yb}}_3{\mathrm{Ga}}_2{\mathrm{Al}}_3{\mathrm{O}}_{12}$ characterized via different experimental techniques and complemented by crystal electric field (CEF) calculations. The magnetic measurements suggest the absence of magnetic long-range order down to 0.1 K, and the ground state is a Kramers doublet with an effective spin $J_{\mathrm{eff}}=1/2$. A small Curie–Weiss temperature and magnetic scaling analysis suggest weak interaction among the magnetic $J_{\mathrm{eff}}=1/2$ entities. The temperature-dependent magnetic susceptibility and magnetic heat capacity could be described by a two-level Schottky function arising from the Zeeman splitting of the ground-state Kramers doublet. The CEF parameters are calculated using the point charge model. After diagonalizing the CEF Hamiltonian, we obtained the CEF energy eigenvalues and the corresponding wave functions. The simulated magnetization and heat capacity using these CEF parameters nicely reproduce our experimental data. The large separation between the ground state and the first excited state doublets in the calculated CEF scheme further supports a $J_{\mathrm{eff}}=1/2$ state at lower temperatures.

In this study, we present a comprehensive analysis of the Raman-active phonon modes in orthorhombic ${\mathrm{LaInO}}_3$ based on a combination of polarization-angle resolved Raman spectroscopy and density functional theory calculations. By using backscattering from multiple crystallographic surface orientations and employing a full symmetry analysis, we identify and assign most of the Raman-active $\mathrm{\Gamma }$-point phonons to their irreducible representations of the $D_{2h}$ point group. A multidimensional hyperspectral fitting procedure allows us to extract the relative Raman tensor elements from the angular dependence of the scattering intensities, even for strongly overlapping modes. First-principles calculations yield the phonon dispersion along high-symmetry directions, the phonon densities of states, atomic displacement patterns, and Raman tensor elements, which are found to be in good agreement with the experiment.

High pressure provides an effective route to activate molecular nitrogen and access nitrogen-rich compounds with unusual bonding motifs. Here we investigate the Eu–N system under pressure by combining attention-coupled neural network (ACNN)-assisted structure searches, first-principles calculations, and laser-heated diamond-anvil-cell experiments. Convex-hull analyses reveal a rich Eu–N phase landscape across 0–100 GPa, including nine thermodynamically stable $\mathrm{Eu}{\mathrm{N}}_x$ phases with nitrogen motifs ranging from isolated or dimeric units to cyclic, chainlike, layered, and molecularly confined configurations. Guided by these predictions, we synthesized a previously unreported $R\overline{3}m {\mathrm{EuN}}_{12}$ phase at 45–56 GPa, representing an experimental realization of this nitrogen-rich europium nitride stoichiometry. ${\mathrm{EuN}}_{12}$ contains dense lattice-confined ${\mathrm{N}}_2$-like dumbbells with a short N–N distance of 1.133 Å at 50 GPa and remains traceable upon decompression to 5 GPa, indicating the robustness of its confined molecular nitrogen units. Electronic-structure and bonding analyses suggest that localized Eu $4f$ states act as a valence-buffering reservoir, moderating Eu-to-nitrogen charge transfer and limiting occupation of ${\mathrm{N}}_2$-derived antibonding states. These results establish the Eu–N system as a rare-earth platform for nitrogen-rich compounds and reveal how pressure, localized $4f$ electrons, and nitrogen-motif evolution cooperate to stabilize high-pressure nitrides with confined molecular nitrogen units.

Control of structural domains in epitaxial thin films of functional materials is a fundamental technique to utilize their intrinsic physical and chemical properties in solid-state devices. In this study, we report on suppression of twisted-domain formation in thin-film growth of polar magnetic semiconductor $\mathrm{AgCrS}{\mathrm{e}}_2$ using pulsed-laser deposition. In exploring simultaneously optimized growth temperature and Ag/Cr composition ratio of supply, we find the critical growth temperature ($T_{\mathrm{sub}}$) for obtaining single ${60}^{\circ }$ domain in $c$-axis-oriented $\mathrm{AgCrS}{\mathrm{e}}_2$ thin film on a lattice-matched (111) plane of the yttria-stabilized zirconia substrate. At temperatures below and above the critical $T_{\mathrm{sub}}$, metastable $0^{\circ }$ domain in addition to the ${60}^{\circ }$ domain emerges, indicating delicate energy balance of thermodynamic stability for obtaining the single-domain structure. On the other hand, surface structural analysis using time-of-flight low-energy atom scattering spectroscopy reveals the presence of two polar orientations along +$Z$ and −$Z$ directions. These findings provide valuable insights into the thin-film growth mechanisms for a family of two-dimensional compounds with rhombohedral lattices.

We present a diffuse neutron and x-ray scattering study of structural as well as spin- and charge-density-wave fluctuations in the electrical insulator $\mathrm{L}{\mathrm{a}}_{2-x}\mathrm{S}{\mathrm{r}}_x\mathrm{Ni}{\mathrm{O}}_4$. This lamellar nickelate is an isostructural analog of the high-temperature cuprate superconductor $\mathrm{L}{\mathrm{a}}_{2-x}\mathrm{S}{\mathrm{r}}_x\mathrm{Cu}{\mathrm{O}}_4$, for which recent experiments uncovered evidence for unusual structural and superconducting fluctuations indicative of rare-region physics due to inherent inhomogeneity unrelated to common point disorder effects. Here we find closely analogous nanoscale orthorhombic fluctuation behavior in $\mathrm{L}{\mathrm{a}}_{2-x}\mathrm{S}{\mathrm{r}}_x\mathrm{Ni}{\mathrm{O}}_4$, including exponential scaling of the diffuse scattering intensity and power-law scaling of the characteristic length with relative temperature. Moreover, our neutron and x-ray scattering data reveal similar behavior for short-range magnetic and charge fluctuations above the respective ordering temperatures. These observations indicate that rare-region effects are a generic feature of perovskite-related structures and lead to universal fluctuations of both structural and electronic degrees of freedom over extended temperature ranges.

The development of ZnO nanowires by the low-temperature, surface scalable, and easily implemented chemical bath deposition technique has been boosted for two decades by the great control over their structural morphology and properties with an excellent uniformity. However, the resulting ZnO nanowires suffer from relatively poor optical properties, which are highly detrimental for their efficient integration into real-world engineering devices. Here, we show that the hydrogen- and deuterium-plasma treatments result in a remarkable increase by more than two orders of magnitude in the intensity of the near‐band edge emission of ZnO nanowires through the formation of surface excitons, along with the large increase in the surface exciton lifetime from about 6 to 48 ps. The enhancement is attributed to an efficient passivation process of the surface defects of ZnO nanowires with hydrogen, further decreasing the density of surface traps from about $4.0\times {10}^{13}\mathrm{c}{\mathrm{m}}^{-2}$ to $3.8\times {10}^{12}\mathrm{c}{\mathrm{m}}^{-2}$, and it is also shown to be highly stable over time. These findings reveal that the structural and optical quality of ZnO nanowires grown by chemical bath deposition through the occurrence of surface excitons induced by hydrogen and deuterium passivation can approach those of much more sophisticated physical and chemical vapor deposition techniques proceeding at higher temperature and under vacuum. Eventually, the present plasma treatments offer a great opportunity to boost the optical quality of ZnO nanowires grown by chemical bath deposition for a vast number of optical and optoelectronics devices, renewing the high interest in the wet chemistry processes.

Soliton states of magnetostatic surface spin waves (MSSWs) hold great potential for nonlinear magnonics, yet their experimental existence remains elusive due to the difficulty in distinguishing them from other coherent states with phase modulations. Here, using phase- and spatiotemporal-resolved Brillouin light scattering spectroscopy, we resolve the phase evolution of MSSWs and identify two distinct nonlinear coherent phases: a dipole gap bright soliton under short-pulse excitation, evidenced by its characteristic phase plateau, and a coherent phase modulation under long-pulse excitation, exhibiting spatiotemporal periodicities—with nearly equal temporal periods in intensity and phase, and a spatial period in intensity linked to the temporal period via the group velocity. This coherent phase modulation originates from the four-magnon scattering, producing a tunable frequency-comb spectrum and displaying power-controlled nonreciprocity. Our work provides phase-resolved verification of MSSW solitons, reveals a coherent phase modulation, and establishes a multidimensional diagnostic framework for controlling nonlinear coherent phases in magnonics.

The dendritic microstructure that develops during solidification of metallic alloys plays a significant role in defining the characteristics of the material. The shape of dendrite tips directly influences the overall dendritic pattern, but in situ characterization of dendrite tips in bulk systems during directional solidification is rare because of experimental complexity. Here, we quantitatively characterize the three-dimensional (3D) tip shapes of dendrites grown during directional solidification of a transparent succinonitrile–0.46 wt% camphor alloy in the microgravity environment of the International Space Station, where convection is suppressed. The 3D reconstruction of the shape of dendrite tips is obtained through the analysis of interferometry images. Results are compared with both sharp-interface theory and 3D phase-field simulations. The experimental results are found to be in reasonably good quantitative agreement with the predictions of microscopic solvability theory and phase-field simulations despite a wider-than-expected scatter in measured tip radii that could be because of measurement uncertainties and other factors.

Building on earlier reports of superconductivity in bulk PtSb, we present a systematic study of superconductivity in epitaxial PtSb(0001) thin films grown on ${\text{SrF}}_2\left(111\right)$. Electrical transport measurements reveal a superconducting transition at $T_{\mathrm{c}}=1.72\mathrm{K}$. The field-induced broadening of the transition and the temperature dependence of the upper critical fields are consistent with type-II superconductivity. We determine the upper critical fields for magnetic fields applied perpendicular and parallel to the film plane and parametrize their temperature dependence using an anisotropic Ginzburg-Landau approach. For a representative film in the intermediate thickness regime ($d=50\mathrm{n}\mathrm{m}$), we obtain coherence lengths of ${\xi }_{ab}\approx 56\mathrm{n}\mathrm{m}$ and ${\xi }_c\approx 14\mathrm{n}\mathrm{m}$. Current-voltage characteristics show sizable critical currents, with a critical current density reaching $J_{\mathrm{c}}\approx 6\times {10}^4\mathrm{A}/{\text{cm}}^2$ at $0.5\mathrm{K}$. These results establish the superconducting properties of epitaxial PtSb thin films and provide a basis for lattice-matched heterostructures within the NiAs-type materials family.

Quantum sensing of meV-scale scattering and absorption of impinging particles with electrons in solid state detectors is a challenging technological advancement with the potential to enable breakthroughs in quantum information applications and studies of fundamental physics. However, a key obstacle for current sensing schemes is the difficulty in distinguishing the signals from particles of interest from false positive signals produced by intrinsic excitations, like phonons or magnons. Here, we propose a technique to selectively detect impinging particles based both on their imparted energy and also their imparted momentum to exploit the variability of dispersion relations amongst sources of meV-scale electronic excitations. By harnessing interfacial orbital hybridization in van der Waals heterostructures of Dirac materials, interlayer charge transfer may be promoted only for pre-selected impinging particles of interest. Using first-principles density functional theory (DFT) calculations of heterostructures of the layered Dirac materials ${\mathrm{ZrTe}}_5$ and ${\mathrm{HfTe}}_5$, we examine the effects of strain and layer number for successfully tuning orbital hybridization in their electronic structure. We demonstrate a proof-or-principle feasibility study for using Dirac materials to construct “dispersion filters” to be leveraged for next-generation meV-scale quantum sensors.

We have identified the optical signature of a variety of basal plane stacking faults (SFs) in AlN, exhibiting from one to five violations of the wurtzite stacking sequence. The unambiguous assignment of the emission energies to specific SFs was achieved by using a combination of scanning transmission electron microscopy and cathodoluminescence experiments performed on the same lamellae. Additional cathodoluminescence experiments have confirmed the spatially direct or indirect nature of the transitions and the role of polarization fields. Ab initio density functional theory (DFT) calculations for the different SF types were performed to determine their formation energies and electronic structures. SF luminescence energies were calculated using the one-dimensional envelope function approximation to solve the effective-mass Schrödinger equation. We find an excellent agreement between experiments and calculations. In particular, the DFT calculations reveal a crossover from momentum-direct to momentum-indirect recombination in the SFs, accounting for the higher emission energy of I3 relative to I2 SFs. This system provides an attractive platform for investigating spatially and momentum-indirect excitons.

Understanding the interplay between lattice dynamics and charge transport is essential for designing high-performance thermoelectric materials. In this work, we systematically investigate the thermoelectric transport properties of Zintl phase ${\mathrm{XInTe}}_2$ (X = Na, K, Rb) based on first-principles calculations. For lattice thermal transport, we apply self-consistent phonon theory (SCP) for the first time in this system and include the bubble diagram correction to accurately capture finite-temperature phonon renormalization. Moreover, the off-diagonal thermal conductivity contribution ${\kappa }_c$ is incorporated into the calculation of lattice thermal conductivity (${\kappa }_L$). Our results show that the enhanced Born effective charge (BEC) and large dielectric constant in ${\mathrm{NaInTe}}_2$ give rise to strong dynamic polarity, which enhances low-frequency phonon scattering through phonon branch softening and leads to a significant reduction in ${\kappa }_L$. In addition, nearly flat mid-frequency phonon branches are mainly associated with localized Na vibrations, exhibiting rattler-like behavior that further strengthens phonon scattering. For electronic transport, we use the amset framework to evaluate carrier transport properties by explicitly considering multiple scattering mechanisms, including grain boundary (MFP), acoustic deformation potential (ADP), ionized impurity (IMP), polar optical phonon (POP), and piezoelectric (PZ) scattering. As a result, p-type ${\mathrm{NaInTe}}_2$ exhibits a maximum $ZT$ of 2.54 at 800 K. When spin-orbit coupling (SOC) is included, the $ZT$ remains as high as 2.02, highlighting its robust thermoelectric performance.

We study the origin of interfacial shallow hole traps appearing in GaN-based metal oxide-semiconductor field-effect transistors (MOSFETs) using density-functional-theory calculations with realistic interfacial models. It is demonstrated that the ${\mathrm{GaO}}_x$ interfacial layer spontaneously formed at the ${\mathrm{GaN}/\mathrm{SiO}}_2$ interfaces, even without conventional point defects such as oxygen vacancies, induces hole traps. The holes are directly trapped at the tail state of amorphous ${\mathrm{GaO}}_x$, which are shown here to consist of $2p$ orbitals of low-coordinated O atoms with relatively high electrostatic potential. When occupied, these states are located just below the GaN valence band maximum, but upon hole localization, they are raised to the mid-gap region and become hole traps as a result of the lengthening of the Ga–O bonds.

Machine learning potentials (MLPs) have significantly advanced global crystal structure prediction by enabling efficient and accurate property evaluations. In this study, global structure searches are performed for 11 bismuth-based binary systems, including Na–Bi, Ca–Bi, and Eu–Bi, under pressures ranging from 0 to 20 GPa, employing polynomial MLPs developed specifically for these systems. The searches reveal numerous compounds not previously reported in the literature and identify all experimentally known compounds that are representable within the explored configurational space. These results highlight the robustness and reliability of the current MLP-based structure search. The study provides valuable insights into the discovery and design of novel bismuth-based materials under both ambient and high-pressure conditions.