Electronic and magnetic properties of quasi-one-dimensional osmium halide OsCl4

Using ab initio density functional theory, we study the electronic and magnetic properties of the van der Waals chain material OsCl4. In the nonmagnetic state, a strongly anisotropic band structure was observed, in agreement with its anticipated one-dimensional crystal geometry. Based on Wannier functions, we found that the four electrons of the 5d Os atom form a low-spin S = 1 state, with a large crystal field between the dxz= yz and dxy orbitals, corresponding to a strong Jahn-Teller distortion (Q(3) < 0). As a consequence, the magnetic properties are mainly contributed by the dxz= yz states. Furthermore, when a Mott gap develops after the introduction of the Hubbard U and Hund coupling J, we found that the staggered spin order is the most likely magnetic state, namely, spins arranged as (up arrow-down arrow-up arrow-down arrow) with pi wavevector along the chain. In addition, the energy differences between various spin states are small, suggesting a weak magnetic exchange coupling along the chain. Our results provide guidance to experimentalists and theorists working on quasi-one-dimensional osmium halides chain materials. Published under an exclusive license by AIP Publishing.

Automated summary

Using ab initio density functional theory, the electronic and magnetic properties of the van der Waals chain material OsCl4 were studied. It was found that in the nonmagnetic state, there is a strongly anisotropic band structure, while a staggered spin order is the most likely magnetic state after the development of a Mott gap. The results provide guidance to experimentalists and theorists working on quasi-one-dimensional osmium halides chain materials.