  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.
