Atypical Highly-Dispersive Band Structure in Putative Amorphous Topological Insulator

ORAL

Abstract

In typical amorphous and highly disordered materials, Anderson Localization guarantees flat valence bands. This effect is so dramatic and pervasive in the amorphous field of study that the density of states is assumed to be momentum-independent, serving as the full characterization of an amorphous system's electronic structure. In this work, we discover an exception to this rule in amorphous Bi2Se3 films. Angle-resolved photoemission spectroscopy uncovers an amorphous surface-state band structure with strong momentum-dependence and spin-momentum locking. We observe a Fermi surface with repeated annuli and reveal a spherically-parameterized momentum-space picture that warrants a re-evaluation of amorphous band structure on the most fundamental level.

*S.C. was supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE1852814 and DGE1106400.

Gordon and Betty Moore Foundation's EPiQS grant GBMF4838

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Presenters

  • Samuel Ciocys

    • University of California, Berkeley

Authors

  • Samuel Ciocys

    • University of California, Berkeley

  • Paul Corbae

    • University of California, Berkeley

  • Daniel Varjas

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology
    • QuTech and Kavli Institute of NanoScience,, Delft University of Technology

  • Adolfo G Grushin

    • University Grenoble Alpes
    • Neel Institute (CNRS)
    • Univ. Grenoble Alpes, CNRS, Grenoble INP,Institut Néel
    • Néel Institute

  • Frances Hellman

    • Physics, University of California, Berkeley
    • University of California, Berkeley
    • University of California, Berkeley, and Lawrence Berkeley National Laboratory
    • University of California Berkeley
    • University of California, Berkeley and Lawrence Berkeley National Laboratory

  • Alessandra Lanzara

    • University of California, Berkeley
    • Physics, University of California, Berkeley