We propose that the quasi-one-dimensional molybdenum selenide compound Tl2-xMo6Se6 is a time-reversal-invariant topological superconductor induced by inter-sublattice pairing, even in the absence of spin-orbit coupling (SOC). No noticeable change in superconductivity is observed in Tl-deficient (0<=x<=0.1) compounds. At weak SOC, the superconductor prefers the triplet d vector lying perpendicular to the chain direction and two-dimensional E2u symmetry, which is driven to a nematic order by spontaneous rotation symmetry breaking. The locking energy of the d vector is estimated to be weak and hence the proof of its direction would rely on tunnelling or phase-sensitive measurements.
@article{arxiv.1711.00815,
title = {Topological superconductor in quasi-one-dimensional Tl2-xMo6Se6},
author = {Shin-Ming Huang and Chuang-Han Hsu and Su-Yang Xu and Chi-Cheng Lee and Shiue-Yuan Shiau and Hsin Lin and Arun Bansil},
journal= {arXiv preprint arXiv:1711.00815},
year = {2018}
}