Understanding how atoms arrange on semiconductor surfaces is critical for growing high-quality thin films for electronic devices. Using quantum-mechanical simulations combined with high-resolution electron microscopy, we discover a previously unknown 1 x 2 surface reconstruction of $\beta {\text{-Ga}}_2{\text{O}}_3(001)$, a leading candidate for next-generation power electronics. In this structure, gallium and oxygen atoms form edge-sharing tetrahedral units on the surface, exhibiting remarkable stability across a wide range of experimental growth conditions. We also find that indium atoms, used as catalysts during growth, preferentially substitute into the surface in cooperative groupings, offering new guidance for optimizing film deposition.

The authors demonstrate the coexistence of $d$-wave altermagnetism and nontrivial band topology in Janus FeSe$X$ ($X$ = S, Te) monolayers. In the nonrelativistic limit, the two-dimensional system exhibits momentum-dependent spin splitting with vanishing net magnetization, a signature of $d$-wave altermagnetic order. Upon inclusion of spin–orbit coupling, a topological gap opens, accompanied by symmetry-protected, spin-polarized edge states. The intrinsic interplay between altermagnetic order and relativistic effects enables robust, low-dissipation spin transport, establishing Janus FeSeX as a compelling platform for next-generation quantum applications.

Ceramic materials containing lanthanide (rare-earth) ions are important to many technologies including solid-state refrigeration, lasers, fuel cells, and the growing field of quantum computing. In this work, the authors investigated a series of four isostructural compounds with different lanthanide ions and compared them with the quantum magnet M’-YbTaO4 recently reported by others. While the lanthanide ions are chemically very similar, the materials display a wide range of electronic and magnetic properties as revealed by magnetometry and physical property measurements and detailed crystallographic analysis, including the use of neutron diffraction for magnetic structure determination.

The electric current flowing through antiferromagnets can be spin-polarized when their magnetic structures break the macroscopic time-reversal symmetry, which leads to the emergence of the tunnel magnetoresistance (TMR) effect in the antiferromagnetic tunnel junction. In this study, the authors calculation the TMR effect from first-principles with the noncollinear antiferromagnet Mn${}_3$Sn as the electrode, and MgO, a typical barrier material, as the insulating spacer. They show that Mn${}_3$Sn/MgO/Mn${}_3$Sn junctions exhibit a sizable TMR effect owing to the spin splitting of Mn${}_3$Sn and the screening effect of MgO. This work will serve as a reasonable benchmark for further development of the antiferromagnetic TMR effect.

We show that the shape of a finite altermagnetic sample can generate a measurable spin polarization, even though these materials exhibit zero net magnetization in the large-system limit. This effect arises from the interplay between anisotropic spin-resolved band structures and the discrete set of allowed electron states in confined geometries. For rectangular samples, unequal dimensions lead to an imbalance between spin populations. We propose transport-based probes to detect this geometry-induced spin polarization, which manifests as characteristic signatures in magnetoresistance. Our results reveal a simple and robust route to controlling spin using sample geometry alone, opening new possibilities for nanoscale spintronic devices based on altermagnets.

Altermagnetism is reshaping fundamental understanding of magnetism, combining zero net magnetization with spin-split electronic bands, all without needing heavy, expensive elements. But how to find these materials efficiently? The authors performed a high-throughput screening of the MAGNDATA database (2287 experimentally characterized magnetic structures) by combining symmetry analysis with spin-polarized DFT. This identified 180 robust altermagnets, both metallic and semiconducting, many previously unreported. Representative cases such as UCr2Si2C, NbMnP, and YRuO3 exhibit particularly large splittings. The authors’ open-access database (https://altermagnets.anyterial.se/) provides full results, and momentum-resolved analysis shows that maximal splitting often occurs away from conventional high-symmetry paths, directly guides future ARPES experiments.

Machine learning potentials (MLPs) have been widely used in predicting the thermal transport properties of $\beta$-Ga${}_2$O${}_3$. However, there are few reports on MLPs specifically considering complex defects in $\beta$-Ga${}_2$O${}_3$. In this study, the authors trained a deep neural network MLP model to quantify how different intrinsic point defects suppress the thermal conductivity of $\beta$-Ga${}_2$O${}_3$. These results provide atomic-level insight into thermal transport in defective $\beta$-Ga${}_2$O${}_3$, offering guidance for thermal-management strategies and establishing a general workflow for investigating thermal physics in complex semiconductor materials.

The emergence of metastable lonsdaleite germanium (2H-Ge) heralds a novel group-IV semiconductor, with the potential to address the longstanding challenge of realizing a direct-gap optical emitter for monolithic integration on Si. In this work, the nature of optical emission from direct-gap 2H-Ge is addressed theoretically. The authors’ first-principles calculations accurately account for measured photoluminescence spectra, and demonstrate that radiative recombination in 2H-Ge is significantly weaker than in a conventional direct-gap semiconductor. Strain-dependent analysis confirms the predicted emergence of an optically bright band gap under uniaxial tension, highlighting that strain engineering presents a promising route to realize 2H-Ge-based emitters for photonics.

In many practical situations – whether during casting, 3D printing, or more generally processing – colloidal suspensions of attractive particles undergo gelation while being subjected to repeated deformations. Although such flows are ubiquitous in industrial and laboratory settings, their impact on the emergence of the gel network remains poorly understood. Here, the authors show that applying oscillatory deformations on a colloidal suspension as it turns into a soft solid can imprint fracture patterns that lead to weaker gels compared to quiescent gelation, while enhancing their ability to dissipate energy. Remarkably, these cracks leave a simple and robust mechanical signature that can be captured by a minimal model, linking fracture to bulk material response. Their results reveal how mechanical perturbations reshape gelation and provide a practical route to design softer, more ductile materials.

Identical insulating particles can exchange electric charge upon contact, a process known as triboelectric charging. This phenomenon plays key roles in natural processes such as dust storms, volcanic eruptions, and planet formation, as well as in many industrial settings. Surprisingly, charge transfer also occurs between particles of the same size and material. We measure charge distributions in large ensembles of oxide particles with carefully controlled sizes and compositions. Highly charged particles arise far more often than expected, resulting in strongly non-Gaussian distributions. Their probability increases systematically with particle size, scaling with surface area. These results place new constraints on microscopic mechanisms of triboelectric charging.

Understanding the atomic evolution from cluster to nanocrystal has long been a challenge in nanoscience. Here, an accurate machine learning potential (MLP) of elemental Pd was developed. The large-scale capacity of this MLP affords long-time simulated annealing for a cross-scale study of Pd${}_n$ nanostructures ($n$=12 - 21856), revealing a continuous transition from discrete clusters to bulk-like nanocrystals and the critical size at which the transition occurs. This study paves the way for studies on other clusters.

Ultrafast transmission electron microscopy, a powerful tool for visualizing ultrafast structural dynamics, is harnessed here to reveal the full-cycle reversible dynamics of five-fold twinned silver nanowires across picosecond to microsecond timescales. On the picosecond timescale, a two-step process was identified: a fast electron-phonon coupling step and a slower step ascribed to hot electron decay due to trap states. Anisotropic phonon-phonon interactions, arising from the one-dimensional structure of the silver nanowires, drive energy transfer from the radial to the axial direction on the nanosecond scale. The subsequent recovery of the lattice occurs on the microsecond scale. These findings pave the way for advanced ultrafast device applications.