Time-reversal-invariant topological superconductivity in n-doped BiH

Despite intense interest and considerable works, definitive experimental evidence for time-reversal-invariant topological superconductivity is still lacking. Hence searching for such superconductivity in real materials remains one of the main challenges in the field of topological material. Previously it has been shown that in the buckled honeycomb lattice structure, hydrogenated single bilayer Bi, namely BiH, is a topological insulator. Here we predict that upon n-type doping, BiH is a time-reversal-invariant topological superconductor. Interestingly the edge states of such a superconductor consist of both helical complex fermion modes and helical Majorana fermion modes.