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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)

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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