Time-reversal-invariant topological superconductors have a full paring gap in the bulk and gapless Majorana states at the edge or on the surface. Here, we theoretically propose topological superconductivity in a doped quantum spin Hall insulator. We study the pairing symmetry of doped SnX film within a two-orbital model, and show that it realizes a topological superconductor when the intraorbital attractive interaction is stronger than the interorbital interaction, which is generic for a doped quantum spin Hall insulator with strong spin-orbit coupling. Edge channels are studied in a tight-binding model numerically. Finally, we discuss the possible topological superconductivity in SnX film by comparing to 3d superconductivity in bulk Sn.
@article{arxiv.1402.4433,
title = {Two-dimensional time-reversal-invariant topological superconductivity in a doped quantum spin Hall insulator},
author = {Jing Wang and Yong Xu and Shou-Cheng Zhang},
journal= {arXiv preprint arXiv:1402.4433},
year = {2014}
}