Strong and Weak 2D Topological Superconductivity in Hidden Quasi-1D Systems

Partly motivated by the newly discovered family of bismuth-based superconductors including LaO$_{1-x}$F$_x$BiS$_2$, we study possible 2D topological superconductivities (TSC) in hidden quasi-1D systems with spin-orbit couplings. By doing RPA calculations and renormalization group (RG) treatment, we theoretically find that in a large portion of the phase diagram with varying interaction strengths and spin-orbit coupling the ground states favors superconductivity with odd-parity pairing, which results in either chiral TSC or time reversal invariant weak-$Z_2$ TSC. We shall discuss several ways to experimentally identify these strong and weak 2D topological superconductivity. Possible applications to the bismuth-based superconductors LaO$_{1-x}$F$_x$BiS$_2$ will also be remarked.