Examining Magnetic Properties and Multiferroicity in the Isostructural CuTSiS (T = Mn and Fe) System Based on the DFT Approach and the Orbital Interaction Analysis.

In the experiment, despite their structural and electronic similarities, CuMnSiS exhibits AFM ordering characterized by a propagation vector = (1/2, 0, 1/2), while CuFeSiS has a different type of AFM ordering with a propagation vector = (1/2, 1/2, 1/2). To unravel how these differences arise, we investigated magnetic properties of CuTSiS (T = Mn and Fe) based on the DFT calculation and an orbital interaction analysis. We suggest that the Cu ion plays an important role in exhibiting different magnetic structures for the isostructural and pseudoisoelectronic CuTSiS (T = Mn and Fe) compounds.

Optical Transitions of a Single Nodal Ring in SrAs_{3}: Radially and Axially Resolved Characterization.

SrAs_{3} is a unique nodal-line semimetal that contains only a single nodal ring in the Brillouin zone, uninterrupted by any trivial bands near the Fermi energy. We performed axis-resolved optical reflection measurements on SrAs_{3} and observed that the optical conductivity exhibits flat absorption up to 129 meV in both the radial and axial directions, confirming the robustness of the universal power-law behavior of the nodal ring. The axis-resolved optical conductivity, in combination with theoretical calculations, further reveals fundamental properties beyond the flat absorption, including the overlap energy of the topological bands, the spin-orbit coupling gap along the nodal ring, and the geometric properties of the nodal ring such as the average ring radius, ring ellipticity, and velocity anisotropy.

Skin-Deep Aspect of Thermopower in BiQ, PbQ, and BiCuQO (Q = Se, Te): Hidden One-Dimensional Character of Their Band Edges Leading to High Thermopower.

ConspectusThermoelectric (TE) materials have received much attention because of their ability to convert heat energy to electrical energy. At a given temperature , the efficiency of a TE material for this energy conversion is measured by the figure of merit , which is related to the thermopower (or Seebeck coefficient) , the thermal conductivity κ, and the electrical conductivity σ of the TE material as = (σ)/κ. BiQ and PbQ (Q = Se, Te) are efficient TE materials with high , although they are not ecofriendly and their stability is poor at high temperature.

Spin-Peierls Distortion of TiPO Causing a Transition from a Magnetic to a Nonmagnetic Insulating State and Its Effect on the Thermoelectric Properties: Density Functional Theory Analysis.

Density functional theory calculations were carried out to probe the nature of the electronic structure change in TiPO before and after its spin-Peierls distortion at 74.5 K, which is characterized by the dimerization in the chains of Ti (d) ions present in TiPO. These calculations suggest strongly that the electronic state of TiPO is magnetic insulating before the distortion, but becomes nonmagnetic insulating after the distortion.

Magnetic Structure and Origin of Insulating Behavior in the BaCuOsO System, and the Role of A-Site Ionic Size in Its Bandgap Opening: Density Functional Theory Approaches.

The magnetic structure and the origin of band gap opening for BaCuOsO were investigated by exploring the spin exchange interactions and employing the spin-orbit coupling effect. It revealed that the double-perovskite BaCuOsO, composed of the 3d (Cu) and 5d (Os) transition metal magnetic ions is magnetic insulator. The magnetic susceptibilities of BaCuOsO obey the Curie-Weiss law, with an estimated Weiss temperature of -13.

Tunable high-temperature itinerant antiferromagnetism in a van der Waals magnet.

Discovery of two dimensional (2D) magnets, showing intrinsic ferromagnetic (FM) or antiferromagnetic (AFM) orders, has accelerated development of novel 2D spintronics, in which all the key components are made of van der Waals (vdW) materials and their heterostructures. High-performing and energy-efficient spin functionalities have been proposed, often relying on current-driven manipulation and detection of the spin states. In this regard, metallic vdW magnets are expected to have several advantages over the widely-studied insulating counterparts, but have not been much explored due to the lack of suitable materials.

Accelerated crystal structure prediction of multi-elements random alloy using expandable features.

Properties of solid-state materials depend on their crystal structures. In solid solution high entropy alloy (HEA), its mechanical properties such as strength and ductility depend on its phase. Therefore, the crystal structure prediction should be preceded to find new functional materials.