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