Fermiology of Strongly Spin-Orbit Coupled Superconductor Sn1-xInxTe and its Implication to Topological Superconductivity

TL;DR

This study uses angle-resolved photoemission spectroscopy to explore the electronic structure of Sn1-xInxTe, revealing topological surface states and band inversion, which suggest potential topological superconductivity in this doped crystalline insulator.

Contribution

It provides direct experimental evidence of topological surface states and band inversion in Sn1-xInxTe, linking its electronic structure to possible topological superconductivity.

Findings

Presence of a topological surface state in Sn1-xInxTe

Band inversion characteristic of topological crystalline insulators

Comparison with Pb1-xTlxTe highlights the role of orbital characteristics

Abstract

We have performed angle-resolved photoemission spectroscopy of the strongly spin-orbit coupled low-carrier density superconductor Sn1-xInxTe (x = 0.045) to elucidate the electronic states relevant to the possible occurrence of topological superconductivity recently reported for this compound from point-contact spectroscopy. The obtained energy-band structure reveals a small holelike Fermi surface centered at the L point of the bulk Brillouin zone, together with a signature of a topological surface state which indicates that this superconductor is essentially a doped topological crystalline insulator characterized by band inversion and mirror symmetry. A comparison of the electronic states with a band-non-inverted superconductor possessing a similar Fermi surface structure, Pb1-xTlxTe, suggests that the anomalous behavior in the superconducting state of Sn1-xInxTe is likely to be related to the peculiar orbital characteristics of the bulk valence band and/or the presence of a topological surface state.