Interplay between spin-orbit coupling and Hubbard interaction in SrIrO3 and related Pbnm perovskite oxides

Article

关键词: DENSITY-FUNCTIONAL THEORY;    TRANSPORT-PROPERTIES;    ELECTRON-GAS;    SR2IRO4;    TRANSITION;    SRRUO3;    STATE;   

DOI  :  10.1103/PhysRevB.86.085149

来源: SCIE

【 摘 要 】

There has been a rapidly growing interest in the interplay between spin-orbit coupling (SOC) and the Hubbard interaction U in correlated materials. A current consensus is that the stronger the SOC, the smaller is the critical interaction U-c required for a spin-orbit Mott insulator, because the atomic SOC splits a band into different total angular momentum bands, narrowing the effective bandwidth. It was further claimed that at large enough SOC, the stronger the SOC, the weaker the U-c, because in general the effective SOC is enhanced with increasing electron-electron interaction strength. Contrary to this expectation, we find that, in orthorhombic perovskite oxides (Pbnm), the stronger the SOC, the bigger the U-c. This originates from a line of Dirac nodes in J(eff) = 1/2 bands near the Fermi level, inherited from a combination of the lattice structure and a large SOC. Due to this protected line of nodes, there are small hole and electron pockets in SrIrO3, and such a small density of states makes the Hubbard interaction less efficient in building a magnetic insulator. The full phase diagram in U vs SOC is obtained, where nonmagnetic semimetal, magnetic metal, and magnetic insulator are found. Magnetic ordering patterns beyond U-c are also presented. We further discuss implications of our finding in relation to other perovskites such as SrRhO3 and SrRuO3.

【 授权许可】

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