Theory of Topological Phases and Topological Band Engineering of Graphene Nanoribbons

ORAL

Abstract

Using first-principles and model Hamiltonian calculations, we show that 1D symmetry-protected topological phases exist in graphene nanoribbons (GNRs). Semiconducting GNRs of different width, edge shape, and terminating unit cells can belong to electronic topological classes characterized by different values of a Z2 invariant. Interfaces between topologically distinct GNRs characterized by different Z2 are predicted to support robust in-gap topological interface states which can be utilized as a tool for material engineering. The experimental realizations of these predictions and rational design of topologically-engineered GNR superlattices synthesized from molecular precursors have been achieved. We present here the theoretical basis and calculations for these states, showing novel robust electronic bands with desirable properties. We discuss how this manifestation of 1D topological phases may be used in future studies of 1D quantum spin physics.

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Presenters

  • Ting Cao

    Physics, UC Berkeley, University of California, Berkeley, Physics Department, UC Berkeley and Geballe Laboratory for Advanced Materials, Stanford University, Physics Department at UC Berkeley and Geballe Laboratory for Advanced Materials at Stanford University, Geballe Laboratory for Advanced Materials, Stanford University

Authors

  • Ting Cao

    Physics, UC Berkeley, University of California, Berkeley, Physics Department, UC Berkeley and Geballe Laboratory for Advanced Materials, Stanford University, Physics Department at UC Berkeley and Geballe Laboratory for Advanced Materials at Stanford University, Geballe Laboratory for Advanced Materials, Stanford University

  • Fangzhou Zhao

    University of California, Berkeley, Physics Department, UC Berkeley and Lawrence Berkeley National Lab

  • Steven G. Louie

    Physics, UC Berkeley, University of California, Berkeley, Department of Physics, University of California, Berkeley, Physics Department, UC Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Physics, University of California at Berkeley, University of California at Berkeley and Lawrence Berkeley National Lab, University of California at Berkeley and Lawrence Berkeley National Laboratory, Physics, University of California, Berkeley, UC Berkeley and Lawrence Berkeley National Lab, Physics, University of California - Berkeley, Physics and Materials Sciences, University of California at Berkeley and Lawrence Berkeley National Laboratory, Lawrence Berkeley National Lab and University of California, Berkeley, University of California - Berkeley, Lawrence Berkeley National Laboratory