Interaction-induced topological orbital phases in tetragonal t2g systems

ORAL

Abstract

We theoretically predict the anomalous orbital Hall(AOH) effect based on an reliable effective two-orbital model. This model reveals four Dirac-like linear dispersion with C$_{4v}$ symmetry. We find a ground state with spontaneous orbital current order driven by inter-orbital Coulomb interaction. The orbital order breaks the degeneracy of Dirac linear dispersion and has topologically nontrivial Chern number $C = \pm 2$. With open boundaries, we show the edge states are topologically protected. We find a new Z$_2$ topological insulating phase protected by time reversal(TR) symmetry and orbital exchange symmetry when spin degrees of freedom are incorporated.

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Authors

  • Yuan-Yen Tai

    Department of Physics and Texas Center for Superconductivity, University of Houston, Univ of Houston Dept of Physics, Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204, USA

  • C.-C. Joseph Wang

    Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos National Lab

  • Jian-Xin Zhu

    Los Alamos National Laboratory, Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA, Theoretical Division and Center for Integrated Technologies, Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Los Alamos National Lab, Theoretical Division and Center for Nonlinear Studies, LANL, Los Alamos, New Mexico 87545, USA, Los Alamos Natl Lab

  • Matthias J. Graf

    Los Alamos National Laboratory, Los Alamos National Lab, Theoretical Division and Center for Nonlinear Studies, LANL, Los Alamos, New Mexico 87545, USA

  • C.S. Ting

    Univ of Houston Dept of Physics, Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204, USA