Comparison of the Fermi Surfaces of Bi$_{2}$Se$_{3}$, Cu$_{x}$Bi$_{2}$Se$_{3}$, and Nb$_{x}$Bi$_{2}$Se$_{3}$
ORAL
Abstract
Topological insulator Bi$_{2}$Se$_{3}$ is made superconducting with Cu and Nb doping. These have been the leading candidates to realize topological superconductivity. To understand the new physics showcased in these system, a detailed knowledge of the electronic structure is needed. We present a comparison of the quantum oscillations in the magnetization and transport of undoped, Cu-doped, and Nb-doped Bi$_{2}$Se$_{3}$. Whereas Cu dopants in Bi$_{2}$Se$_{3}$ simply raise the chemical potential indicated by a larger Fermi pocket, Nb-doped Bi$_{2}$Se$_{3}$ has two distinct oscillation frequencies. The multiple frequencies observed in the quantum oscillations indicate that the doping changes the band structure of Nb-doped Bi$_{2}$Se$_{3}$ with interesting implications for its topological nature.
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