Using density functional theory calculations, we investigated possible Weyl semimetal (WSM) phases in antimony arsenide ordered alloys ${\mathrm{Sb}}_{1-x}{\mathrm{As}}_x$ ($x=0,1/6,1/3,1/2,2/3,5/6,1$). We find WSM phases for all As compositions of ${\mathrm{Sb}}_{1-x}{\mathrm{As}}_x$ with broken inversion symmetry, in contrast to ${\mathrm{Bi}}_{1-x}{\mathrm{Sb}}_x$ where only compositions $x=1/2$ and $5/6$ were predicted to exhibit WSM phases. The WSM phases in ${\mathrm{Sb}}_{1-x}{\mathrm{As}}_x$ are characterized by the presence of 12 Weyl points, located within 55 meV from the Fermi level in the case of $x=1/2$. The robust spin-orbit coupling strength and Berry curvature in these alloys produce large spin-Hall conductivity in the range of 176–602 ($\hslash /e$)(S/cm), comparable to that in the BiSb alloys. Finally, ${\mathrm{Sb}}_{0.5}{\mathrm{As}}_{0.5}$ is predicted to be almost lattice matched to GaAs(111), with the Fermi level within the gap of the semiconductor, facilitating growth and characterization, and thus, offering promising integration with conventional semiconductors.

Iron is a major component of the cores of the Earth and inhabited exoplanets. Its phase diagram at extreme pressures (P) and temperatures (T) is the subject of extensive debate. While recent experiments provide evidence for the stability of the body-centered cubic (bcc) phase, several theoretical studies point to the stability (even though marginal) of the hexagonal close-packed phase (hcp). None of those studies considered the itinerant magnetism of iron at extreme conditions. We compute the high-pressure phase diagram of Fe using density functional theory-based molecular dynamics (DFT MD) in which the paramagnetic nature of Fe is treated within the model of thermally induced longitudinal spin fluctuations (LSF). The LSF DFT MD with 16 valence electrons favors bcc phase stability. Two-phase large-scale simulations with quantum accurate machine learning potentials provide us with both melting and hcp-bcc phase boundaries. The computed phase diagram agrees with most of the experimental data and solves most of the numerous controversies. We conclude that the account for magnetism results in the new physics of iron under extreme conditions and brings the theory in agreement with experiment and seismic data. We expect that the approach we use can be applied to other metals where itinerant magnetism is important.

Machine-learned interatomic potentials (MLIPs) are becoming an essential tool in materials modeling. However, optimizing the generation of training data used to parametrize the MLIPs remains a significant challenge. This is because MLIPs can fail when encountering local enviroments too different from those present in the training data. The difficulty of determining a priori the environments that will be encountered during molecular dynamics simulation necessitates diverse, high-quality training data. This study investigates how training data diversity affects the performance of MLIPs using the Ultra-Fast force field (${\mathrm{UF}}^3$) to model amorphous silicon nitride. We employ expert and autonomously generated data to create the training data and fit four force field variants to subsets of the data. Our findings reveal a critical balance in training data diversity: insufficient diversity hinders generalization, while excessive diversity can exceed the MLIP's learning capacity, reducing simulation accuracy. Specifically, we found that the ${\mathrm{UF}}^3$ variant trained on a subset of the training data, in which nitrogen-rich structures were removed, offered vastly better prediction and simulation accuracy than any other variant. By comparing these ${\mathrm{UF}}^3$ variants, we highlight the nuanced requirements for creating accurate MLIPs, emphasizing the importance of application-specific training data to achieve optimal performance in modeling complex material behaviors.

Here, we present a comprehensive study on the magnetic evolution processes in ${\mathrm{AgCrSe}}_2$ using both neutron scattering and theoretical calculations. The development of magnetic short-range correlation with decoupled interlayer interactions is confirmed between 55 and 200 K. Significant magneto-crystalline anisotropy energy around 0.1 meV of ${\mathrm{Cr}}^{3+}$ is identified that mainly contributes to the robust existence of the in-plane magnetic correlations in the magnetic short-order regime. Furthermore, the indirect superexchange interactions through Cr-Se-Ag-Se-Cr path between the adjacent ${\mathrm{CrSe}}_6$ octahedral layers is also demonstrated. In combination with the mutual coupling among multiple degrees of freedom (spin, phonon, lattice, and dipole), we reveal the key role of the freezing of ${\mathrm{Ag}}^{+}$ fluctuations in preventing interlayer exchange interactions from decoupling.

Cathode materials ${\mathrm{Li}}_{1-x}{\mathrm{Ni}}_{1-z}{\mathrm{Co}}_{z/2}{\mathrm{Mn}}_{z/2}{\mathrm{O}}_2$ with $z=1/5$ (NCM811), $z=2/5$ (NCM622), or $z=2/3$ (NCM111) in (i) the pristine state, (ii) charged to $x=0.5$ or $x=0.65$, and (iii) discharged after having been charged previously were characterized by x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), direct current (DC) and alternating current (AC) magnetometry, heat capacity, and nuclear magnetic resonance (NMR) spectroscopy. The magnetic properties of these layered oxides are decisively determined by ${\mathrm{Ni}}^{2+}$ ions that have migrated from the transition metal (TM) layer to the Li layer and that are magnetically coupled to the Ni, Co, or Mn cations occupying neighboring sites within the adjacent TM layers. For the pristine and discharged states, this cluster formation causes a bifurcation between the zero-field-cooled (ZFC) and the field-cooled (FC) susceptibility vs temperature curve (which sets in continuously below about 100 K) and is responsible for the appearance of a broad maximum of the imaginary ${\chi }^{\prime \prime }$ susceptibility vs temperature curve that is centered around 14, 23, and 25 K for pristine NCM111, NCM622, and NCM811, respectively. The charged states with reduced ${\mathrm{Ni}}^{2+}$ amount do no longer show these features pointing to a strongly reduced cluster formation ability. Further, three-dimensional (frustrated) magnetic long-range ordering that leads to a broad local maximum in the heat capacity curve and to another abrupt bifurcation of the ZFC/FC susceptibility vs temperature curve (both observable slightly below 10 K) are additional features that all compositions (and states of charge) have in common. With increasing Ni to Co/Mn ratio, this low-temperature magnetic transition exhibits a more pronounced “partial” spin-glass-like characteristic as inferred from the frequency shift of the local AC susceptibility maximum. The results from AC/DC magnetometry and heat capacity measurements return complementary information to what can be inferred from XRD, XAS, and NMR investigations about the Ni to Co/Mn ratio, the Li/Ni disorder, and the TMs' oxidation states. The systematic investigation of samples with different Ni to Co/Mn ratios (going from NCM811 via NCM622 to NCM111) and with different oxidation states of the TMs (at different states of charge) allows for a better understanding of how the magnetic phenomena are correlated with the (real) structure and electronic properties in these layered oxide cathode materials.

The ${MA}_2{Z}_4$ family presents a promising platform for the development of next-generation functional devices due to their remarkable physical properties. Inspired by the intercalation architecture of ${MA}_2{Z}_4$, where the inner ${MA}_2$ core layer is intercalated by the outer AZ sublayers, we computationally explore the intercalation of a hexagonal boron nitride (hBN) monolayer with outer AN (A = Si, Ge) layers. This results in the formation of novel intercalated $\mathrm{B}{A}_2{\mathrm{N}}_3$ monolayers, which are characterized by an “AN-hBN-AN” sandwichlike structure. Using density functional theory simulations, we demonstrate that $\mathrm{B}{A}_2{\mathrm{N}}_3$ is a polar semiconductor with strain-tunable electronic characteristics, optical activities, piezoelectricity, and water-splitting capabilities. The conduction band edge exhibits strong mechanical-valley coupling, with its position in momentum space being tunable across different valleys under applied strain. Optical calculations further reveal strong, broadband optical absorption in the deep ultraviolet spectral range. Intriguingly, the hBN core layer buckles and undergoes an unusual intercalation-induced centrosymmetry breaking effect, resulting in sizable out-of-plane piezoelectricity and an exceptionally strong built-in electric dipole, which enhances water-splitting efficiency. These findings position $\mathrm{B}{A}_2{\mathrm{N}}_3$ as a compelling two-dimensional multifunctional semiconductor and highlight the potential of intercalation architecture as a versatile strategy for designing a wide range of synthetic monolayers beyond traditional bulk van der Waals materials.

The silver fluoride ${\mathrm{Ag}}_3{\mathrm{F}}_5$ consists structurally of square-planar units formed by four fluoride ions coordinated to a central silver ion, which possesses a partially filled $d$ subshell and the formal valence of $+5/3$. In this study, we demonstrate that the previously published crystal structure of ${\mathrm{Ag}}_3{\mathrm{F}}_5$ is unstable due to the Jahn-Teller effect, arising from the presence of two energetically degenerate $d_{x^2-y^2}$ states sharing a single electron hole. Through a full structural relaxation within the $\mathrm{DFT}+U$ framework, we identified a new crystal structure for ${\mathrm{Ag}}_3{\mathrm{F}}_5$ with reduced symmetry and an energy gain of 151 meV per formula unit relative to the published structure. In this relaxed structure, magnetic chains are formed by silver ions with an electronic hole occupying the $d_{x^2-y^2}$ orbital. These results highlight the crucial role of electron correlation effects and related structural distortions in determining the properties of such materials.

The rich physics of nickelates has garnered widespread attention, particularly for their superconductivity and the prominent $\mathrm{Ni}\text{−}{d}_{x^2-y^2}$-dominated Fermi surface. Motivated by the ${\mathrm{Ni}}^{1+\delta }$ superconductivity in infinite-layer ${\mathrm{NdNiO}}_2$ ($T_c=15\mathrm{K}$) and high-pressure superconducting ${\mathrm{La}}_3{\mathrm{Ni}}_2{\mathrm{O}}_7$ ($T_c=80\mathrm{K}$), we designed a (${\mathrm{SrNiO}}_2{)}_2/{\left({\mathrm{LaTiO}}_3\right)}_1$ superlattice with a two-dimensional confined bilayer ${\mathrm{NiO}}_2$. ${\mathrm{LaTiO}}_3$ acts as an electron donor, transferring a full electron to the ${\mathrm{NiO}}_2$ double layers due to the electronegativity difference between Ni(1.91) and Ti(1.54). This charge transfer transforms the Fermi surface from a multiorbital character, resembling that of ${\mathrm{NdNiO}}_2$, into one dominated purely by ${\mathrm{Ni}}^{1+\delta }\text{−}{d}_{x^2-y^2}$ orbitals. Factors that limited the transition temperature in ${\mathrm{NdNiO}}_2$, such as $5d\text{−}3d$ hybridization, self-doping between Nd and Ni atoms, and the weak $p\text{−}d$ hybridization between Ni and O atoms, are effectively suppressed and enhanced, respectively. The nearest-neighbor $e_g$ hoppings closely resemble those in undoped infinite-layer ${\mathrm{NdNiO}}_2$, though they are smaller than those found in high-pressure ${\mathrm{La}}_3{\mathrm{Ni}}_2{\mathrm{O}}_7$. Similar to ${\mathrm{La}}_3{\mathrm{Ni}}_2{\mathrm{O}}_7$, this superlattice exhibits a low-spin magnetic state with instability stemming from nearly degenerate magnetic ground states. Additionally, F doping in ${\mathrm{NiO}}_2$ double layers can be used to fine tune the Ni valence state and the magnetic coupling, simulating the effects of oxygen pressure in the preparation. Our research offers new insights into the mechanisms driving high-$T_c$ superconductivity in nickelates under ambient pressure, emphasizing the pivotal role of heterostructure engineering in these processes.

In this paper, we present a comprehensive study of the CeAlSi and NdAlGe system, focusing on its quantum transport properties. Our investigation reveals the presence of weak antilocalization in magnetoresistance of both samples. The semiclassical model and Hikami-Larkin-Nagaoka fitting indicate the presence of strong spin-orbit coupling and quantum interference effects arising from three-dimensional bulk states. Additionally, we observe pronounced Shubnikov-de Haas (SdH) oscillations, with a dominant frequency of 20.74 T, extending to temperatures as high as 50 K for CeAlSi. Similarly, NdAlGe also exhibits SdH oscillations at magnetic fields above 5 T with a fundamental frequency of 28.39 T, within the temperature range of 1.8 K to 9 K. By performing Lifshitz-Kosevich fitting on the SdH oscillations, we extract approximately $\pi$-Berry phase in both samples, further confirming the nontrivial topology of the band structure in these materials. The nature of SdH oscillations and Landau level index fitting indicates the dominance of Zeeman splitting and $4f$ electron exchange interactions in these compounds. Additionally, the position of the Weyl fermions relative to the Fermi energy, along with other parameters such as the cross-sectional area of the Fermi surface, effective mass, lifetime of charge carriers, Dingle temperature, mobility, and charge-carrier density, is also determined from the SdH oscillations. These findings provide valuable insights into the quantum transport phenomena in ferromagnetic CeAlSi and NdAlGe, highlighting their importance as platforms for exploring type-II Weyl semimetal behavior. Furthermore, their high mobility and low effective mass demonstrate their potential for applications in low-power electronic and high-speed communication devices.

The interplay between linearly dispersing, or Dirac-like, and flat electronic bands, for instance, in the kagome ferromagnets, has attracted attention due to a possible interplay between topology and electronic correlations. Here, we report the synthesis, structural, electrical, and magnetic properties of a single-crystalline ferromagnetic compound, namely ${\mathrm{Fe}}_{1/3}{\mathrm{CrTe}}_2$ or ${\mathrm{FeCr}}_3{\mathrm{Te}}_6$, which crystallizes in the $P\overline{3}m1$ space group instead of the $I2/m$ previously reported for ${\mathrm{FeCr}}_2{\mathrm{Te}}_4$. Electronic band structure calculations reveal type-II Dirac nodes and relatively flat bands near the Fermi level (${\varepsilon }_F$). This compound shows onset Curie temperature $T_{\text{c}}\simeq 120\mathrm{K}$, followed by an additional ferromagnetic transition near $T_{\text{c2}}\sim 92.5\mathrm{K}$. Below $T_{\text{c}}, {\mathrm{FeCr}}_3{\mathrm{Te}}_6$ displays a pronounced anomalous Hall effect, as well as sizable coercive fields that exceed ${\mu }_{0}H=1$ T at low $T\mathrm{s}$. However, a scaling analysis indicates that the anomalous Hall effect results from a significant intrinsic contribution, as expected from the calculations, and also from the extrinsic mechanism, i.e., scattering. The extrinsic contribution probably results from occupational disorder at the 1b Fe-site within the van der Waals gap of the ${\mathrm{CrTe}}_2$ host. We also observe evidence for a topological Hall component superimposed onto the overall Hall response, suggesting the presence of chiral spin textures akin to skyrmions in this centrosymmetric system. Their possible presence will require experimental confirmation.

With the widespread application of nanomaterials in micro-nano devices, phonon transport control has become an indispensable part of thermal management. In this work, we propose an X+EA hybrid optimization strategy based on evolutionary algorithms (EAs) to regulate phonon transport across nanostructures. Due to the inconvenient hyperparameters tuning associated with EAs, we conduct grid searches on the hyperparameter configurations of three typical EAs: genetic algorithm (GA), particle swarm optimization (PSO), and simulated annealing (SA), resulting in more suitable parameter ranges. Compared to previous nanostructure design work using Bayesian optimization (BO) and Monte Carlo tree search (MCTS), we find that EAs exhibit robust structural design capabilities and extremely low optimization costs, particularly the GA with the fewest hyperparameters. Furthermore, we develop a highly compatible X+EA hybrid optimization framework, where X can be substituted with the optimization results of any algorithm and used as the initial structures in the subsequent running of EAs. Among various hybrid optimizations with nonstrict hyperparameter settings, the global search capability of BO+GA even rivals that of BO, while reducing optimization time by over 95%. And MCTS+GA effectively resolves the issue of MCTS alone yielding only a few local optima. The proposed X+EA framework can adapt to the nanostructure design with high degrees of freedom or large candidates.

Identifying and understanding interfacial magnetic structures of transition-metal oxides are of great importance not only for fundamental physics but also for potential device applications. Among them, manganite and ruthenate heterostructures have attracted considerable interest due to their intriguing interfacial properties induced by complex magnetic interactions. Here, we report the observation of dramatic buffer-layer dependence of ferromagnetism in ultrathin $\left(\mathrm{L}{\mathrm{a}}_{2/3}\mathrm{C}{\mathrm{a}}_{1/3}\right)\mathrm{Mn}{\mathrm{O}}_3$ (LCMO)-based heterostructures. Though all trilayers are nonmetallic, the $\mathrm{SrRu}{\mathrm{O}}_3$-buffered LCMO trilayer exhibits enhanced ferromagnetism with the Curie temperature ($T_{\mathrm{C}}\sim 198\mathrm{K}$) much higher than for $\mathrm{CaRu}{\mathrm{O}}_3$ ($T_{\mathrm{C}}\sim 99\mathrm{K}$)- and $\mathrm{SrTi}{\mathrm{O}}_3$ ($T_{\mathrm{C}}\sim 42\mathrm{K}$)-buffered counterparts, as well as the monolithic LCMO films with similar thickness. Combining atomically resolved scanning transmission electron microscopy imaging with electron energy loss spectroscopy mapping, we reveal that asymmetric interfaces exist in the $\mathrm{SrRu}{\mathrm{O}}_3$ buffered trilayer, with one exhibiting 1 unit-cell Sr diffusion into LCMO, which is responsible for the $T_{\mathrm{C}}$ enhancement. In contrast, charge transfer, which has been proposed previously as a possible mechanism, is excluded in this study. Our results may pave a promising road toward effective atomic control of interfacial magnetism.

In this paper, magnetic properties of formate perovskite $\left[{\left({\mathrm{CH}}_3\right)}_2{\mathrm{NH}}_2\right]\mathrm{Cu}{\left(\mathrm{HCOO}\right)}_2\left({\mathrm{NO}}_3\right)$ (DMACu-${\mathrm{NO}}_3$) single crystals are reported. ${\mathrm{Cu}}^{2+}$ ions feature an $S=1/2$ rectangular lattice in the $bc$ plane, which can be considered as a weakly frustrated spatially anisotropic square lattice. Upon cooling, a canted antiferromagnetic order is developed below $T_{\mathrm{N}}=21.5\mathrm{K}$ with an easy-plane anisotropy perpendicular to the $a$ axis. When the magnetic field is applied along the $b$ axis, a field-induced transition appears around 0.05 T at 2 K. In comparison with the one-dimensional chain antiferromagnet $\left[{\left({\mathrm{CH}}_3\right)}_2{\mathrm{NH}}_2\right]\mathrm{Cu}{\left(\mathrm{HCOO}\right)}_3$, the dimensionality switch in DMACu-${\mathrm{NO}}_3$ is originated from the orbital reorientation on half Cu ions after replacing 1/3 HCOO ligands with ${\mathrm{NO}}_3$ linkers.

Time-resolved, synchrotron x-ray diffraction methods coupled to gas and powder gun shock experiments are used to study twinning, detwinning, and melting in magnesium alloy AZ31B-H24. The x-ray diffraction data show that when this cold-rolled polycrystalline metal is shock-compressed to 9 GPa in the rolling direction (corresponding to a pressure-temperature state well within the hcp-phase region), $\left\{10\overline{1}2\right\}$ extension twinning is triggered. Upon release from this shocked state, detwinning is observed. For a shock pressure of 53 GPa, diffraction data show a fully amorphous phase at late times after impact, suggesting complete melting upon release has occurred. Results from theoretical-numerical modeling augment the x-ray diffraction data when the metal is shock-compressed to 53 GPa, predicting a corresponding peak Hugoniot temperature of 2990 K. If the shocked material is fully solid at 53 GPa peak stress, the release isentrope is theoretically predicted to intersect the experimental melt curve of magnesium AZ31B-H24 at a pressure of 23.2 GPa and temperature of 2380 K. The solid-liquid phase transition initiates at this intersection point. Calculated results show that when the release pressure and temperature subsequently drop to 4.8 GPa and 1360 K along a fit to legacy experimental melt data (i.e., melt curve) for magnesium AZ31B-H24, the solid-liquid transition concludes; afterwards the fully liquid-phase metal releases isentropically to zero stress.

Intrinsic ferromagnetic materials with nontrivial topological properties provide a fertile ground to explore exotic quantum properties, such as the quantum anomalous Hall effect, large tunneling magnetoresistance, etc., which would have potential applications in next-generation spintronic devices. In this work, combining experimental and theoretical studies, we find that in a newly synthesized natural bulk van der Waals ${\mathrm{MnSb}}_2\mathrm{T}{\mathrm{e}}_4/{\left(\mathrm{S}{\mathrm{b}}_2\mathrm{T}{\mathrm{e}}_3\right)}_2$ superlattice, the competing magnetic interactions give rise to a fragile ferromagnetic ground state, which whereas very easily enters into the antiferromagnetic states at higher temperatures. Moreover, the system can be forced into a ferromagnetic state by a very small vertical magnetic field. Especially, our calculations reveal that ${\mathrm{MnSb}}_2\mathrm{T}{\mathrm{e}}_4/{\left(\mathrm{S}{\mathrm{b}}_2\mathrm{T}{\mathrm{e}}_3\right)}_2$ system in different magnetic configurations always keeps staying in the axion-insulator state. The axion-insulator state can be converted into a Weyl semimetal with hole doping, manifested by the notable intrinsic anomalous Hall effect. Our work thus provides an intrinsic ferromagnetic topological material which can be tuned into versatile topological phases by temperature, magnetic field, as well as carrier doping.

The miniaturization of electronic devices has led to the prominence, in technological applications, of semiconductor thin films that are only a few nanometers thick. In spite of intense research, the thickness-dependent resistivity or conductivity of semiconductor thin films is not understood at a fundamental physical level. We develop a theory based on quantum confinement which yields the dependence of the concentration of intrinsic carriers on the film thickness. The theory predicts that the resistivity $\rho$, in the 1–10 nm thickness range, increases exponentially as $\rho \sim exp(\mathrm{const}/L^{1/2})$ upon decreasing the film thickness $L$. This law is able to reproduce the remarkable increase in resistivity observed experimentally in Si thin films, whereas the effect of surface scattering (Fuchs-Sondheimer theory) alone cannot explain the data when the film thickness is lower than 10 nm.

Past research has often correlated a magnet's hysteresis width with its magnetocrystalline anisotropy constant ${\kappa }_1$. Based on this relationship, a common approach to reducing magnetic hysteresis has been to develop alloys with ${\kappa }_1$ as close to zero as possible. Contrary to this view, we show that magnets with large ${\kappa }_1$ can have small hysteresis for specific combinations of magnetoelastic constants and applied stresses. Using our recently developed and validated micromagnetics framework, we systematically investigate the interplay of material constants (${\lambda }_{100},c_{11},c_{12}$, ${\kappa }_1$), applied stresses (${\sigma }_{\mathrm{R}}$), and needle domains to collectively lower the energy barrier for magnetization reversal. This energy barrier approach enables us to quantify the effects of magnetoelastic interactions, in addition to magnetocrystalline anisotropy, on magnetic hysteresis. Our findings show a mathematical relationship: ${\kappa }_1=\alpha (c_{11}-c_{12}){({\lambda }_{100}+\beta {\sigma }_{11})}^2$ for which magnetic hysteresis can be minimized for a uniaxial residual stress ${\sigma }_{\mathrm{R}}={\sigma }_{11}{\widehat{\mathbf{e}}}_1\otimes {\widehat{\mathbf{e}}}_1$ (and for some constants $\alpha ,\beta$). These results serve as quantitative guidelines to design magnetic alloys with small hysteresis, and potentially guide the discovery of soft magnets outside the traditional ${\kappa }_1\to 0$ region.

In this paper, we investigate the evolution of crystal structure, magnetic, thermodynamic, and spin correlation behaviors in a series of double perovskite materials ${\mathrm{Sr}}_2{\mathrm{NiMo}}_{1-x}{\mathrm{W}}_x{\mathrm{O}}_6$ $(0\le x\le 1)$ using magnetic susceptibility (dc and ac), specific heat, and neutron diffraction measurements. The magnetic ${\mathrm{Ni}}^{2+}$ ($3d^8$, spin-1) and ${\mathrm{Mo}}^{6+}/{\mathrm{W}}^{6+}$ $(4d^0/5d^0)$ ions are arranged alternatively in the crystal structure where the (super)exchange interactions between ${\mathrm{Ni}}^{2+}$ follow Ni-O-Mo/W-O-Ni pathways. Our magnetization measurements indicate an antiferromagnetic state in the parent compound $(x=0.0)$ with ordering temperature $T_N\sim 80$ K, is suppressed with W substitution, showing $T_N\sim$ 60 K for the other end compound $(x=1.0)$. With W substitution, further, an additional peak accompanied by a bifurcation between zero-field-cooled and field-cooled moments is observed at low temperature in magnetization data, which is due to a coexisting glassy phase, as identified using ac susceptibility in the representative $x$ = 0.5 sample. The specific heat measurements show an anomaly across $T_N$ while its magnetic component follows a $C_m\propto T^3$ behavior at low temperature. Our detailed neutron diffraction measurements show an ordered antiferromagnetic ground state with magnetic propagation vector $k=(0.5, 0, 0.5)$, where the magnetic moment has been detected close to the expected value of $\sim 2$ ${\mu }_B/{\mathrm{Ni}}^{2+}$ across the series. While the W substitution does not alter both lattice and magnetic structures in this series, it lowers the $T_N$ and induces sizable magnetostructural coupling across the ordering temperature. Given that W and Mo have similar ionic radii, charge states, and (non)magnetic behaviors but differ in their $d$ character, the present substitution of W has a remarkable effect on the ground state magnetic properties, which calls for an investigation using microscopic probes and theoretical calculations.

Using coarse-grained molecular dynamics simulations, we analyze the shock compression response of fully neutralized poly(ethylene-co-acrylic acid) ionomers. We investigate systems with uniform chain lengths that are sufficiently short to avoid entanglements, while varying the number of charged particles per chain and temperature. In the preshocked state, charged particles group into clusters, with packing features controlled by charge density and temperature. During shock compression we find that the speed of sound in the system is controlled by density, that here depends on charge number and temperature. The increase in shock widths as the density of charged particles increases indicates that shock attenuation is influenced by the presence of charged particles. Strong shocks can break the charged particle clusters, similarly to the homogenization effect achieved by increasing temperature, thereby contributing to the redistribution of energy introduced by the shock.

Two-dimensional semiconductors have been identified as promising channel materials in nanoelectronic devices for sustaining Moore's law. Searching for suitable metal electrodes is critical to fabricating high-performance nanoscale channel field-effect transistors (FETs). In the present article, we adopt first-principles calculations to explore adsorption energy, adsorption structures, and electronic structures of H, Li, B, C, N, O, F, and Na adsorption on monolayer blue phosphorene (BlueP). Our calculated results indicate that all adatoms have minor impacts on the structure of BlueP except for B, C, and F adatoms. H, Li, Na, and N adsorption results in metallic properties of adsorption systems, but O adsorption preserves its semiconductor property. We also use density functional theory coupled with the nonequilibrium Green function method to investigate the transport properties of BlueP-based FETs with Li-adsorbed and Na-adsorbed BlueP electrodes. Our calculated results indicate that Li-adsorbed BlueP is superior to Na-adsorbed BlueP. Especially, BlueP-based FET with 9 nm channel length exhibits an excellent on-state current of $\approx 1540.3\mu \mathrm{A}/\mu \mathrm{m}$, distinctly exceeding the International Technology Roadmap for Semiconductors requirements for high-power devices. These results imply that Li-adsorbed BlueP may act as an appropriate electrode material for BlueP-based FETs, meaning that low contact resistance can be obtained by surface adsorption strategy. In addition, the results of carrier density, device conductance, projected density of states, and real-space scattering state show that O adsorption on BlueP channel can improve the electrical transport performance of the device. This implies that absorbing suitable elements on the semiconductor channel can effectively improve device performance, thus providing guidance for the design of future FETs.