Surface optical study of topological insulator Bi2Se3

ORAL

Abstract

We report the observation of optical surface second harmonic generation from the (111) surface of Bi2Se3 using ultrafast laser pulses. We demonstrate that second harmonic generation is sensitive to both the surface crystal structure as well as the surface carrier density, which we tune through surface molecular doping. Protected nodes in the second harmonic circular dichroism spectroscopy provide a method to study time-reversal symmetry breaking effects from a single surface in a contact free manner.

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Authors

  • David Hsieh

    • MIT
    • Department of Physics, Massachusetts Institute of Technology, Cambridge MA 02139

  • James McIver

    • Department of Physics, MIT, Cambridge, MA 02139
    • Department of Physics, Massachusetts Institute of Technology, Cambridge MA 02139

  • Darius Torchinsky

    • MIT
    • Department of Physics, Massachusetts Institute of Technology, Cambridge MA 02139

  • Dillon Gardner

    • Department of Physics, Massachusetts Institute of Technology, Cambridge MA 02139

  • Young Lee

    • MIT
    • Department of Physics, Massachusetts Institute of Technology, Cambridge MA 02139
    • Massachusetts Institute of Technology

  • Nuh Gedik

    • Massachusetts Institute of Technology
    • MIT
    • Department of Physics, MIT, Cambridge, MA 02139
    • Department of Physics, Massachusetts Institute of Technology, Cambridge MA 02139