Applications of a Novel Quantum Interband Index in Condensed Matter: Topological Insulators, Optical Selection Rules, and Beyond

ORAL

Abstract

The physical significance of a novel gauge-invariant interband index T proposed in [1] is not immediately clear in condensed matter systems. In this talk, we present numerical calculations of the index T in various systems. Calculations of T in loops around valleys of the Haldane model for the anomalous quantum Hall effect give distinct integer numbers with behavior partly reminiscent of different types of Chern numbers (such as spin or valley). For loops containing more/less than 1 Dirac point, our calculations reveal perplexing results including a link to the sign of local Berry curvature. We further connect this index to recently discovered optical selection rules [2-4] and demonstrate other physical effects related to T.

[1] Phys. Rev. A. 97.3 (2018): 032124
[2] Phys. Rev. Lett. 120.8 (2018): 087402
[3] Phys. Rev. Lett. 120.7 (2018): 077401
[4] Science 358.6365 (2017): 907-910

*This work is supported by the Provost Fellowship from the Department of Physics at the University of Washington.

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Presenters

  • Tharindu Warnakulasooriya Fernando

    • Physics, University of Washington

Authors

  • Tharindu Warnakulasooriya Fernando

    • Physics, University of Washington

  • Ting Cao

    • University of Washington
    • Department of Physics, University of California at Berkeley and Lawrence Berkeley National Laboratory
    • Physics, University of Washington
    • Department of Materials Science and Engineering, University of Washington and Geballe Laboratory for Advanced Materials, Stanford University

  • Congjun Wu

    • University of California, San Diego
    • Department of Physics, University of California, San Diego
    • Physics, University of California, San Diego