Physical Review Materials

As a rare strongly correlated kagome metal, CsCr${}_3$Sb${}_5$ hosts exotic intertwined orders, quantum criticality, and pressure-induced superconductivity. Here, the authors report a range of anomalous magnetotransport signatures and identify a potential additional electronic order characterized by $T_3$. Their measurements reveal unconventional magnetotransport features linked to this anomaly, including increased conductivity, a nontrivial temperature dependence of the Hall coefficient, and a pressure-enhanced anomalous-Hall-like effect. Combined with Hall and mobility-spectrum analyses, they show that the electronic carrier profile is severely altered below $T_3$, pointing to the presence of an additional electronic order in CsCr${}_3$Sb${}_5$.

Kinetomagnetism describes magnetization, or related pseudovector responses, induced by linear momentum k or symmetry-equivalent external stimuli. Its necessary and sufficient symmetry condition is broken parity-time (PT) symmetry, which also permits spin-split electronic bands. The authors establish a connection between kinetomagnetism and altermagnetism within the generalized SAM classification. All altermagnets can exhibit kinetomagnetism: S- and M-type altermagnets support even-order responses, whereas A-type altermagnets support odd-order responses. This symmetry-based framework unifies piezomagnetism, higher-order nonlinear Hall responses, and spin-splitting torques. By analyzing spin-rotation symmetries in the spin configurations of candidate materials, it also identifies when nonrelativistic spin-split bands can contribute to these responses.

The structurally complex tetragonal sigma (σ) phase provides a unique platform for investigating the interplay between chemical disorder, electronic structure, and superconductivity, particularly in Re-based alloys, in which unconventional superconductivity has been widely discussed. Here, the authors investigate superconductivity in σ-phase Re–X (X = V, Nb, and Ta) alloys, covering 3d, 4d, and 5d transition-metal substitutions, as well as in a derived medium-entropy alloy incorporating multiple transition metals. The narrow stability range of the σ phase highlights the sensitivity of its structural stabilization to chemical composition and valence electron concentration. Magnetization, electrical resistivity, and specific heat measurements establish bulk type-II superconductivity in all compounds. The electronic heat capacity is consistent with a fully gapped, weak-coupling BCS state. These findings highlight σ-phase Re-based alloys as model systems for exploring the roles of structural complexity, chemical disorder, and spin-orbit coupling in superconductivity.

This study investigates the atomic-scale structure and stability of Guinier-Preston I (GP-I) zones in Al-Zn-Mg alloys. Large-scale simulations combine molecular dynamics and Monte Carlo techniques using a newly developed atomic cluster expansion (ACE) interatomic potential. Annealing of supersaturated solid solutions leads to the formation of nearly spherical GP-I zones composed of ordered Mg-Zn building blocks, with Zn atoms frequently shifting toward interstitial positions. The resulting precipitates exhibit distinct core-shell chemistry: a Zn-rich core surrounded by an Mg-enriched interfacial region, yielding an overall Zn/Mg ratio of approximately 1.5. Simulated HAADF-STEM images reproduce key features observed experimentally. At elevated temperatures, GP-I zones preferentially dissolve rather than transform directly into more stable precipitates, while vacancies and divacancies can stabilize small solute clusters even at high temperatures.

The authors have developed Bend Contour Electron Tomography (BCET), a computational framework that turns conventional electron microscope images into quantitative maps of morphology and strain tensors in ultrathin materials, which are essential for understanding and designing their mechanical, magnetic, and optical properties. Rather than scanning a sample point-by-point, BCET analyzes full-field images by decoding bend contours created as electrons scatter through a deformed crystal. Combining images acquired at different viewing angles then allows the reconstruction of both the membrane shape and its local strain. BCET offers an accessible route to efficiently mapping nanoscale deformation and, ultimately, tracking how ultrathin materials respond dynamically to light, heat, and applied forces.

Ultrashort laser pulses offer a route to controlling quantum coherence in atomically thin semiconductors. Using first-principles simulations, the authors investigate coherent excitonic oscillations in monolayer tungsten disulfide. They reveal how coupling between excitonic states shapes these oscillations and how an additional resonance modifies their dynamics. Building on this microscopic understanding, they propose a sequence of laser pulses that generates and regenerates coherent oscillations on demand. The results connect the microscopic physics of interacting excitons with an optical control scheme, suggesting opportunities for ultrafast optical switching and future devices that use quantum coherence to manipulate and process information in solid-state materials.

Changing the atomic composition of a semiconductor offers a powerful way to tailor its properties. This study explores atomically thin alloys of molybdenum, sulfur, and selenium by probing their excitons, Coulomb-bound electron-hole pairs. By gradually replacing selenium with sulfur, the study reveals how alloying modifies exciton emission energies, atomic lattice vibrations, spin-orbit coupling and polarization of emitted light. Combining complementary optical spectroscopy techniques with first-principles calculations, the work provides a more comprehensive understanding of how alloy composition influences excitonic behavior and its connection to electronic, vibrational, and spin-valley properties.

The authors report a comprehensive, multitechnique study of bismuth oxide growth on Au(111) under varying temperatures and oxygen exposures. Combining synchrotron-based spectroscopy, diffraction, and scanning tunneling microscopy, they elucidate the structural evolution during oxidation and annealing. Oxidation produces multiple oxide domains, including a structure consistent with the (201) surface of β-Bi${}_2$O${}_3$, while annealing drives phase separation and Au redistribution to the oxide surface. These processes induce substantial electronic modifications and lower the work function to 3.4 eV, highlighting the potential of Bi${}_2$O${}_3$ as a low-work-function interlayer for contact engineering in two-dimensional semiconductor devices.

Uncovering hidden structural dynamics in an organic conductor Organic conductors host a remarkable interplay between molecular structure and electronic properties. In \kappa-(BETS)${}_2$Mn(N(CN)${}_2$)${}_3$, a multiferroic candidate exhibiting electronic ferroelectricity below the metal-to-insulator transition at 25 K, we identify the microscopic origin of a long-standing anomaly near 100 K. Resistance noise spectroscopy, thermal expansion, and computational modeling reveal compelling evidence for a glass-like freezing of dicyanamide ligands in the anion layer. Despite occurring outside the conducting layer, this structural transition leaves a pronounced fingerprint on the charge-carrier dynamics. Our results demonstrate that slow structural fluctuations in the anion network can strongly influence electronic behavior, providing new insight into the role of donor-anion coupling and disorder in organic quantum materials.

The authors assess the performance of the recently developed non-empirical Wannier-localized, optimally tuned, screened range-separated hybrid (WOT-SRSH) functional for prototypical antiferromagnetic insulators: MnO, NiO, hematite, and chromia. By comparing WOT-SRSH with established hybrid functionals, self-consistent quasiparticle GW, dynamical mean-field theory, and available experimental data, they demonstrate its ability to offer quantitative improvement in the description of fundamental band gaps, spin magnetic moments, photoemission, and optical spectra. These results establish WOT-SRSH as a promising framework for predictive studies of the electronic, magnetic, and optical properties of magnetic insulators.