Interplay of orbital effects and nanoscale strain in topological crystalline insulators

 · Invited

Abstract

Orbital degrees of freedom can have pronounced effects on the fundamental properties of electrons in solids. In addition to influencing bandwidths, gaps, correlation strength and dispersion, orbital effects have been implicated in generating novel electronic and structural phases, such as Jahn-Teller effect and colossal magnetoresistance. In this talk I will describe how we use a combination of STM studies and first principles calculations to reveal the mechnaism by which the orbital nature of bands can result in non-trivial effects of strain on band structure. Using quasiparticle interference we study the influence of strain on the electronic structure of a heteroepitaxial thin film of a topological crystalline insulator SnTe. By mapping the effects of uniaxial strain on the band structure we find a surprising effect where strain applied in one direction has the most pronounced influence on the band structure along the perpendicular direction. Our theoretical calculations indicate that this can be attributed to the orbital nature of the conduction and valence bands. Our results imply that a microscopic model capturing strain effects on band structure must include a consideration of the orbital nature of bands.

*U.S. Department of Energy (DOE), Scanned Probe Division under award DE-SC0014335

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Presenters

  • Vidya Madhavan

    • Physics, Univ of Illinois - Urbana
    • Physics, Univ of Illinois
    • University of Illinois - Urbana Champaign
    • Physics, University of Illinois
    • University of Illinois at Urbana-Champaign
    • Physics, Univeristy of Illinois at Urbana-Champaign
    • Univ of Illinois - Urbana
    • Department of Physics, University of Illinois
    • Department of Physics, Univ of Illinois - Urbana-Champaign

Authors

  • Daniel Walkup

    • NIST
    • Center for Nanoscale Science and Technology, NIST / Maryland NanoCenter, University of Maryland
    • Center for Nanoscale Science and Technology, NIST -Natl Inst of Stds & Tech
    • Center for Nanoscale Science and Technology, National Institute of Standards and Technology
    • Center for Nanoscale Science and Technology, NIST

  • Badih Assaf

    • Physics, Univ of Illinois
    • Department of Physics, Ecole Normale Supérieure

  • Kane Scipioni

    • Physics, Univ of Illinois

  • R. Sankar

    • National Taiwan University
    • Center for Condensed Matter Sciences, National Taiwan University

  • Guoqing Chang

    • National University of Singapore
    • Institute of Physics, Academica Sinica
    • Institute of Physics, Academia Sinica
    • Princeton Univ
    • National U. of Singapore

  • Fangcheng Chou

    • National Taiwan University
    • Center for Condensed Matter Sciences, National Taiwan University

  • Hsin Lin

    • Academia Sinica
    • National University of Singapore
    • Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore
    • Institute of Physics, Academica Sinica
    • Institute of Physics, Academia Sinica
    • National U. of Singapore
    • Natl Univ of Singapore
    • National University of Signapore

  • Ilija Zeljkovic

    • Physics, Boston College
    • Boston Coll
    • Department of Physics, Boston Coll

  • Vidya Madhavan

    • Physics, Univ of Illinois - Urbana
    • Physics, Univ of Illinois
    • University of Illinois - Urbana Champaign
    • Physics, University of Illinois
    • University of Illinois at Urbana-Champaign
    • Physics, Univeristy of Illinois at Urbana-Champaign
    • Univ of Illinois - Urbana
    • Department of Physics, University of Illinois
    • Department of Physics, Univ of Illinois - Urbana-Champaign