First-principles study on spin-orbital entangled Jeff =3/2 moments and related properties of the lacunar spinel compound GaTa4Se8

Abstract

To predict and analyze the material properties for realistic systems in the first-principles approach is always demanded. In this dissertation, we will present the first-principles study for the lacunar spinel compound, GaTa$_4$Se$_8$. GaTa$_4$Se$_8$is the material that contains 5d transition metal atoms, which implies that both spin-orbit coupling and electron-electron interaction are important. We used density functional theory (DFT), DFT + U, and dynamical mean-eld theory to study the electronic, magnetic, and structural properties of GaTa$_4$Se$_8$. The parameterization of GaTa$_4$Se$_8$ is also done based on DFT electronic structure. Based on the calculation results and the experimental collaboration, we discuss the material characteristics, including intriguing magnetism, insulator-metal transition, and superconductivity.