Nanosecond dynamics in intrinsic topological insulator Bi<sub>2-x</sub>Sb<sub>x</sub>Se<sub>3</sub> revealed by time-resolved optical reflectivity

ORAL

Abstract

Bi2Se3 is an ideal three-dimensional topological insulator in which the chemical potential can be brought into the bulk band gap with antimony doping. Here, we utilize ultrafast time-resolved transient reflectivity to characterize the photoexcited carrier decay in Bi2-xSbxSe3 nanoplatelets. We report a substantial slowing of the bulk carrier decay rate in bulk-insulating Bi2-xSbxSe3 as compared to n-type bulk-metallic Bi2Se3 at low temperatures, which approaches 0.30 ns-1 in the zero pump fluence limit. This long-lived decay is correlated across different fluences and antimony concentrations, revealing unique decay dynamics not present in n-type Bi2Se3, namely the slow bimolecular recombination of bulk carriers.

*This work is supported by National Science Foundation Grant DMR-1838532.

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Presenters

  • Adam Gross

    • University of California, Davis

Authors

  • Adam Gross

    • University of California, Davis

  • Yasen Hou

    • Massachusetts Institute of Technology

  • Antonio Rossi

    • Lawrence Berkeley National Laboratory
    • University of California, Davis
    • Lawrence Berkeley National Lab, Advanced Light Source
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • Dong Yu

    • University of California, Davis

  • Inna Vishik

    • University of California, Davis
    • Physics and Astronomy, University of California, Davis