Electronic state induced by spin-orbit coupling in 5d transition metal oxides

5d遷移金属酸化物においてスピン軌道相互作用により誘起される電子状態

大西 弘明  

Onishi, Hiroaki

To clarify a crucial role of a spin-orbit coupling in the emergence of novel spin-orbital states in 5d-electron compounds such as , we investigate ground-state properties of a -orbital Hubbard model by numerical methods. In the absence of the spin-orbit coupling, the ground state is a spin singlet, while it turns into a singlet state in terms of the effective total angular momentum with the increase of the strength of the spin-orbit coupling. We find the so-called complex orbital state, in which real , , and orbital states are mixed with complex number coefficients. Regarding the multipole state, we observe that the dipole and octupole correlations are enhanced in the spin-orbit-induced phase. We will also discuss the spin, orbital, and multipole states for other electron numbers.