Topological superconductor in quasi-one-dimensional Tl_2−xMo₆Se₆

Search for topological superconductors would be the most attractive subject among all the topological materials in part because the Majorana fermions they allow at boundaries are of potential applications in quantum computation. In this work, we propose that the quasi-one-dimensional molybdenum selenide compound Tl_2−xMo₆Se₆ is a time-reversal-invariant topological superconductor induced by inter-sublattice pairing. Weak spin-orbit coupling will pin the triplet d vector lying perpendicular to the chain direction and results in the two-dimensional E_2u superconductivity with a concurrent nematic order. We estimate the locking energy of the d vector to be weak and hence the proof of its direction would rely on tunnelling or phase-sensitive measurements.