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arXiv · 2006.01716

Massive suppression of proximity pairing in topological (Bi$_{1-x}$Sb$_{x})_2$Te$_3$ films on niobium

Joseph A. Hlevyack·Sahand Najafzadeh·Meng-Kai Lin·Takahiro Hashimoto·Tsubaki Nagashima·Akihiro Tsuzuki·Akiko Fukushima·Cédric Bareille·Yang Bai·Peng Chen·Ro-Ya Liu·Yao Li·David Flötotto·José Avila·James N. Eckstein·Shik Shin·Kozo Okazaki·T. -C. Chiang
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Abstract

Interfacing bulk conducting topological Bi$_2$Se$_3$ films with s-wave superconductors initiates strong superconducting order in the nontrivial surface states. However, bulk insulating topological (Bi$_{1-x}$Sb$_{x})_2$Te$_3$ films on bulk Nb instead exhibit a giant attenuation of surface superconductivity, even for films only two-layers thick. This massive suppression of proximity pairing is evidenced by ultrahigh-resolution band mappings and by contrasting quantified superconducting gaps with those of heavily n-doped topological Bi$_2$Se$_3$/Nb. The results underscore the limitations of using superconducting proximity effects to realize topological superconductivity in nearly intrinsic systems.

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Joseph A. Hlevyack, Sahand Najafzadeh, Meng-Kai Lin, Takahiro Hashimoto, Tsubaki Nagashima, Akihiro Tsuzuki, Akiko Fukushima, Cédric Bareille, Yang Bai, Peng Chen, Ro-Ya Liu, Yao Li, David Flötotto, José Avila, James N. Eckstein, Shik Shin, Kozo Okazaki, T. -C. Chiang. 2020-06-02. Massive suppression of proximity pairing in topological (Bi$_{1-x}$Sb$_{x})_2$Te$_3$ films on niobium. https://doi.org/10.1103/physrevlett.124.236402

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