Quantized thermal Hall conductance and the topological phase diagram of a superconducting bismuth bilayer

Two-dimensional topological superconductors with chiral edge modes are predicted to possess a quantized thermal Hall effect proportional to the Chern number, exactly half that for chiral topological insulators. However, not much work has been done in identifying the quantized heat conductance in the literature, even for some of the standard models of topological superconductivity. Here we introduce a model based on a proximity induced superconducting bismuth bilayer and directly calculate the thermal Hall conductance of this lattice model. This model serves as a demonstration of the state of the art possible in such a calculation, as well as introducing an interesting paradigmatic topological superconductor with a rich phase diagram. We demonstrate the quantized thermal Hall plateaus in several different topological phases and compare this to numerical calculations of the Chern number, as well as analytical calculations of the Chern number's parity invariant. We demonstrate that it is possible to get a reasonable topological phase diagram from the quantized thermal Hall calculations. The technique used can be applied to a wide range of models directly in real space.