Pb-doped <i>p</i>-type Bi<sub>2</sub>Se<sub>3</sub> thin films via interfacial engineering

ORAL

Abstract

Due to high density of native defects, the topological insulator (TI), Bi2Se3, is naturally n-type. Although Bi2Se3 can be converted into p-type by substituting 2+ ions for Bi, only light elements such as Ca have been so far effective as the compensation dopant. Considering that strong spin-orbit coupling (SOC) is essential for the topological surface states, a light element is undesirable as a dopant, because it weakens the strength of SOC. In this sense, Pb, the heaviest 2+ ion located right next to Bi in the periodic table, is the most ideal p-type dopant for Bi2Se3. However, Pb-doping has not achieved p-type Bi2Se3 both in thin films and bulk crystals. Here, by utilizing an interface engineering, we achieved the first Pb-doped p-type Bi2Se3 thin films. Furthermore, at heavy Pb-doping, the mobility is substantially higher than that of Ca-doped samples, indicating that Pb is a less disruptive dopant than Ca. With this SOC-preserving counter-doping, it is now possible to fabricate Bi2Se3 with tunable Fermi levels without compromising their topological properties. [1]

[1] J. Moon, et al, Phys. Rev. Materials 4, 024203 (2020)

*This work was supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative (GBMF4418) and National Science Foundation (NSF) Grant No. EFMA-1542798.

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Presenters

  • Jisoo Moon

    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey
    • Department of Physics & Astronomy, Rutgers, The State University of New Jersey

Authors

  • Jisoo Moon

    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey
    • Department of Physics & Astronomy, Rutgers, The State University of New Jersey

  • Zengle Huang

    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey
    • Rutgers University

  • Weida Wu

    • Rutgers Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, USA
    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey
    • Rutgers University
    • Department of Physics and Astronomy, Rutgers University

  • Seongshik Oh

    • Rutgers University, New Brunswick
    • Department of Physics and Astronomy, Rutgers, The State University of New Jersey
    • Rutgers, The State University of New Jersey
    • Department of Physics & Astronomy, Rutgers, The State University of New Jersey