Observation of coexisting weak localization and superconducting fluctuations in strained Sn1-xInxTe thin films

TL;DR

This study reveals the coexistence of weak localization, antilocalization, and superconducting fluctuations in strained Sn1-xInxTe thin films, providing insights into their quantum effects and pairing mechanisms relevant for topological superconductivity.

Contribution

It demonstrates the simultaneous presence of multiple quantum effects in strained Sn1-xInxTe thin films and links these effects to the material's trivial valence band states and superconducting behavior.

Findings

Weak localization observed in superconducting samples

Enhanced conductivity above Tc indicating quantum coherence

Superconductivity likely originates from trivial valence band states

Abstract

Topological superconductors have attracted tremendous excitement as they are predicted to host Majorana zero modes that can be utilized for topological quantum computing. Candidate topological superconductor Sn1-xInxTe thin films (0<x<0.3) grown by molecular beam epitaxy and strained in the (111) plane are shown to host three coexisting quantum effects: localization, antilocalization and superconducting fluctuations above the critical temperature Tc. An analysis of the normal state magnetoresistance reveals these effects. Weak localization is consistently observed in superconducting samples, indicating that superconductivity originates dominantly from trivial valence band states that may be strongly spin-orbit split. A large enhancement of the conductivity is observed above Tc, indicating that quantum coherent quasiparticle effects coexist with superconducting fluctuations. Our results motivate a re-examination of the debated pairing symmetry of this material when subjected to quantum confinement and lattice strain.