Raimundas Sereika, Vytautas Magnus University, Fri, March 25, 2022, 10am – 11am
The structure of Na2OsO4 is characteristic of quasi-1-D anisotropy, reflecting a notable chain structure in which each chain comprises edge-shared OsO6 octahedra. At ambient conditions this sample adopts hexagonal lattice and is magnetically silent in its ground state with characteristics of a narrow-band-gap insulator (or semiconductor), rather than a Mott insulator. The energy gap in this system is triggered by the axial compression of the OsO6 octahedra with a negligible role of spin-orbit coupling. Since the magnetically silent state was directly related to the OsO6 octahedral distortion, I probed the impact on the structure by applying hydrostatic pressure. My study revealed that pressure causes semiconductor-to-metal transition and strongly increases the distortion in the OsO6 site which in turn creates a variety of electronically related features.