Microscopic study of a spin-orbit-induced Mott insulator in Ir oxides

Hiroshi Watanabe, Tomonori Shirakawa, Seiji Yunoki

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135 Citations (Scopus)

Abstract

Motivated by recent experiments of a novel 5d Mott insulator in Sr 2IrO4, we have studied the two-dimensional three-orbital Hubbard model with a spin-orbit coupling λ. The variational Monte Carlo method is used to obtain the ground state phase diagram with varying an on-site Coulomb interaction U as well as λ. It is found that the transition from a paramagnetic metal to an antiferromagnetic insulator occurs at a finite U=UMI, which is greatly reduced by a large λ, characteristic of 5d electrons, and leads to the "spin-orbit-induced" Mott insulator. It is also found that the Hund's coupling induces the anisotropic spin exchange and stabilizes the in-plane antiferromagnetic order. We have further studied the one-particle excitations by using the variational cluster approximation and revealed the internal electronic structure of this novel Mott insulator. These findings are in agreement with experimental observations on Sr 2IrO4.

Original languageEnglish
Article number216410
JournalPhysical Review Letters
Volume105
Issue number21
DOIs
Publication statusPublished - 2010 Nov 19
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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