Connection between -electron correlations and magnetic excitations in UTe.

The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry and points and disperse along the crystallographic -axis. In applied magnetic fields to at least = 11 T along the , the magnetism is found to be field-independent in the ( 0) plane.

Metamagnetic transition and meta-stable magnetic state in Co-doped FeGaTe.

The transition between the ferromagnetic (FM) and anti-ferromagnetic (AFM) phases in van der Waals (vdW) magnets has been extensively studied since the discovery of vdW magnets, due to the importance of both transitions within a single material. Recently, among vdW magnets, FeGaTe (FGaT) has garnered significant attention for its robust FM properties that remain stable above room temperature. Also, the FM to AFM phase transition in this material has been achieved through substitutional Co-atom doping at Fe sites.

Broken Kramers Degeneracy in Altermagnetic MnTe.

Altermagnetism is a newly identified fundamental class of magnetism with vanishing net magnetization and time-reversal symmetry broken electronic structure. Probing the unusual electronic structure with nonrelativistic spin splitting would be a direct experimental verification of an altermagnetic phase. By combining high-quality film growth and in situ angle-resolved photoemission spectroscopy, we report the electronic structure of an altermagnetic candidate, α-MnTe.

IrGe: A Predicted Weyl-Metal with a Chiral Crystal Structure.

Polycrystalline IrGe was synthesized by annealing elements at 800 °C for 240 h, and the composition was confirmed by energy-dispersive X-ray spectroscopy. IrGe adopts a chiral crystal structure (space group 321) instead of a polar crystal structure (3), which was corroborated by the convergent-beam electron diffraction and Rietveld refinements using synchrotron powder X-ray diffraction data. The crystal structure features layers of IrGe polyhedra along the axis, and the layers are connected by edge- and corner-sharing.

Multi-order graph attention network for water solubility prediction and interpretation.

The water solubility of molecules is one of the most important properties in various chemical and medical research fields. Recently, machine learning-based methods for predicting molecular properties, including water solubility, have been extensively studied due to the advantage of effectively reducing computational costs. Although machine learning-based methods have made significant advances in predictive performance, the existing methods were still lacking in interpreting the predicted results.

Multifunctional CuTSiS (T = Mn and Fe): Polar Semiconducting Antiferromagnets with Nonlinear Optical Properties.

CuTSiS (T = Mn and Fe) polycrystalline and single-crystal materials were prepared with high-temperature solid-state and chemical vapor transport methods, respectively. The polar crystal structure (space group 2) consists of chains of corner-sharing and distorted CuS, Mn/FeS, and SiS tetrahedra, which is confirmed by Rietveld refinement using neutron powder diffraction data, X-ray single-crystal refinement, electron diffraction, energy-dispersive X-ray spectroscopy, and second harmonic generation (SHG) techniques. Magnetic measurements indicate that both compounds order antiferromagnetically at 8 and 14 K, respectively, which is supported by the temperature-dependent (100-2 K) neutron powder diffraction data.

LiMoO: Polar Crystal Structure with Infinite Edge-Sharing Molybdenum Octahedra.

Polycrystalline LiMoO was prepared in a sealed Mo crucible at 1380 °C for 48 h using the conventional high-temperature solid-state method. The polar tetragonal crystal structure (space group 4) is confirmed based on the Rietveld refinement of powder neutron diffraction and Li/Li solid-state NMR. The crystal structure features infinite chains of MoO (i.

Band theoretical approaches to topological physics in strongly-correlated-electron Kondo systems.

First-principles band structure theory on the basis of the density functional theory (DFT) plays an essential role in the investigation of topological properties of weakly-correlated systems. DFT band structures show clear bulk band crossings for Weyl and Dirac semimetals, and surface band crossings for topological insulators and topological-crystalline insulators. In contrast, for strongly-correlated-electron systems, their topological properties are relatively less explored because the simple DFT does not work properly in describing the electronic structures of strongly-correlatedelectrons.

Iridate LiIrO: An Antiferromagnetic Insulator.

A polycrystalline iridate LiIrO material was prepared via heating LiO and IrO starting materials in a sealed quartz tube at 650 °C for 48 h. The structure was determined from Rietveld refinement of room-temperature powder neutron diffraction data. LiIrO adopts the nonpolar space group 3̅ with Li atoms occupying the tetrahedral and octahedral sites, which is supported by the electron diffraction and solid-state Li NMR.

Optical Properties of the Infinite-Layer La_{1-x}Sr_{x}NiO_{2} and Hidden Hund's Physics.

We investigate the optical properties of the normal state of the infinite-layer La_{1-x}Sr_{x}NiO_{2} using density functional theory plus dynamical mean-field theory. We find a correlated metal which exhibits substantial transfer of spectral weight to high energies relative to the density functional theory. The correlations are not due to Mott physics, which would suppress the charge fluctuations and the integrated optical spectral weight as we approach a putative insulating state.

TlIrO: A Pauli Paramagnetic Metal, Proximal to a Metal Insulator Transition.

A polycrystalline sample of TlIrO was synthesized by high-pressure and high-temperature methods. TlIrO crystallizes in the cubic pyrochlore structure with space group 3̅ (No. 227).

Ultrafast Triggering of Insulator-Metal Transition in Two-Dimensional VSe.

The transition-metal dichalcogenide VSe exhibits an increased charge density wave transition temperature and an emerging insulating phase when thinned to a single layer. Here, we investigate the interplay of electronic and lattice degrees of freedom that underpin these phases in single-layer VSe using ultrafast pump-probe photoemission spectroscopy. In the insulating state, we observe a light-induced closure of the energy gap, which we disentangle from the ensuing hot carrier dynamics by fitting a model spectral function to the time-dependent photoemission intensity.

Ambient and High Pressure CuNiSb: Metal-Ordered and Metal-Disordered NiAs-Type Derivative Pnictides.

The mineral Zlatogorite, CuNiSb, was synthesized in the laboratory for the first time by annealing elements at ambient pressure (CuNiSb-AP). Rietveld refinement of synchrotron powder X-ray diffraction data indicates that CuNiSb-AP crystallizes in the NiAs-derived structure (31, #164) with Cu and Ni ordering. The structure consists of alternate NiSb and CuSb octahedral layers via face-sharing.

A Pressure-Induced Inverse Order-Disorder Transition in Double Perovskites.

Given the consensus that pressure improves cation ordering in most of known materials, a discovery of pressure-induced disordering could require recognition of an order-disorder transition in solid-state physics/chemistry and geophysics. Double perovskites Y CoIrO and Y CoRuO polymorphs synthesized at 0, 6, and 15 GPa show B-site ordering, partial ordering, and disordering, respectively, accompanied by lattice compression and crystal structure alteration from monoclinic to orthorhombic symmetry. Correspondingly, the long-range ferrimagnetic ordering in the B-site ordered samples are gradually overwhelmed by B-site disorder.

Low Energy Band Structure and Symmetries of UTe_{2} from Angle-Resolved Photoemission Spectroscopy.

The compound UTe_{2} has recently been shown to realize spin triplet superconductivity from a nonmagnetic normal state. This has sparked intense research activity, including theoretical analyses that suggest the superconducting order parameter to be topologically nontrivial. However, the underlying electronic band structure is a critical factor for these analyses, and remains poorly understood.

Publisher Correction: Temperature-dependent excitonic superfluid plasma frequency evolution in an excitonic insulator, TaNiSe.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Exploitable Magnetic Anisotropy of the Two-Dimensional Magnet CrI.

Magnetic anisotropy often plays a central role in various static and dynamic properties of magnetic materials. In particular, for two-dimensional (2D) van der Waals materials, as inferred from the Mermin-Wagner theorem, it is an essential prerequisite for stabilizing ferromagnetic order. In this work, we carry out first-principles calculations for a CrI monolayer and investigate how its magnetic anisotropy is interrelated to adjustable parameters governing the underlying electronic structure.

Origins of the odd optical observables in plutonium and americium tungstates.

A series of trivalent f-block tungstates, MWO(OH)(HO) (M = La, Ce, Pr, Nd, and Pu) and AmWO(OH), have been prepared in crystalline form using hydrothermal methods. Both structure types take the form of 3D networks where MWO(OH)(HO) is assembled from infinite chains of distorted tungstate octahedra linked by isolated MO bicapped trigonal prisms; whereas AmWO(OH) is constructed from edge-sharing AmO square antiprisms connected by distorted tungstate trigonal bipyramids. PuWO(OH)(HO) crystallizes as red plates; an atypical color for a Pu(iii) compound.

High temperature singlet-based magnetism from Hund's rule correlations.

Uranium compounds can manifest a wide range of fascinating many-body phenomena, and are often thought to be poised at a crossover between localized and itinerant regimes for 5f electrons. The antiferromagnetic dipnictide USb has been of recent interest due to the discovery of rich proximate phase diagrams and unusual quantum coherence phenomena. Here, linear-dichroic X-ray absorption and elastic neutron scattering are used to characterize electronic symmetries on uranium in USb and isostructural UBi.

Correlated materials design: prospects and challenges.

The design of correlated materials challenges researchers to combine the maturing, high throughput framework of DFT-based materials design with the rapidly-developing first-principles theory for correlated electron systems. We review the field of correlated materials, distinguishing two broad classes of correlation effects, static and dynamics, and describe methodologies to take them into account. We introduce a material design workflow, and illustrate it via examples in several materials classes, including superconductors, charge ordering materials and systems near an electronically driven metal to insulator transition, highlighting the interplay between theory and experiment with a view towards finding new materials.

Temperature-dependent excitonic superuid plasma frequency evolution in an excitonic insulator, TaNiSe.

An interesting van der Waals material, TaNiSe has been known one of strong excitonic insulator candidates since it has very small or zero bandgap and can have a strong exciton binding energy because of its quasi-one-dimensional crystal structure. Here we investigate a single crystal TaNiSe using optical spectroscopy. TaNiSe has quasi-one-dimensional chains along the a-axis.

Layer-Confined Excitonic Insulating Phase in Ultrathin Ta2NiSe5 Crystals.

Atomically thin nanosheets, as recently realized using van der Waals layered materials, offer a versatile platform for studying the stability and tunability of the correlated electron phases in the reduced dimension. Here, we investigate a thickness-dependent excitonic insulating (EI) phase on a layered ternary chalcogenide Ta2NiSe5. Using Raman spectroscopy, scanning tunneling spectroscopy, and in-plane transport measurements, we found no significant changes in crystalline and electronic structures as well as disorder strength in ultrathin Ta2NiSe5 crystals with a thickness down to five layers.

Electronic Structure of YbB_{6}: Is it a Topological Insulator or Not?

To finally resolve the controversial issue of whether or not the electronic structure of YbB_{6} is nontrivially topological, we have made a combined study using angle-resolved photoemission spectroscopy (ARPES) of the nonpolar (110) surface and density functional theory (DFT). The flat-band conditions of the (110) ARPES avoid the strong band bending effects of the polar (001) surface and definitively show that YbB_{6} has a topologically trivial B 2p-Yb 5d semiconductor band gap of ∼0.3  eV.

Evidence for Anionic Excess Electrons in a Quasi-Two-Dimensional Ca2N Electride by Angle-Resolved Photoemission Spectroscopy.

Angle-resolved photoemission spectroscopy (ARPES) study of a layered electride Ca2N was carried out to reveal its quasi-two-dimensional electronic structure. The band dispersions and the Fermi-surface map are consistent with the density functional theory results except for a chemical potential shift that may originate from the high reactivity of surface excess electrons. Thus, the existence of anionic excess electrons in the interlayer region of Ca2N is strongly supported by ARPES.