Multiple odd-parity superconducting phases in bilayer transition metal dichalcogenides

Abstract

We study unconventional superconductivity in a two-dimensional locally noncentrosymmetric triangular lattice. The model is relevant to bilayer transition metal dichalcogenides with 2H b stacking structure, for example. The superconducting instability is analyzed by solving the linearized Eliashberg equation within the random phase approximation. We show that ferromagnetic fluctuations are dominant owing to the existence of disconnected Fermi pockets near van Hove singularity, and hence odd-parity spin-triplet superconductivity is favored. In the absence of the spin-orbit coupling, we find that odd-parity f -wave superconducting state is stabilized in a wide range of carrier density and interlayer coupling. Furthermore, we investigate impacts of the layer-dependent staggered Rashba and Zeeman spin-orbit coupling on the superconductivity. Multiple odd-parity superconducting phase diagrams are obtained as a function of the spin-orbit coupling and Coulomb interaction. Especially, a topological chiral p-wave pairing state is stabilized in the presence of a moderate Zeeman spin-orbit coupling. Our results shed light on a possibility of odd-parity superconductivity in various ferromagnetic van der Waals materials.

Laser-induced topological $s$-wave superconductivity in bilayer transition metal dichalcogenides

“…Our main conclusion is that the TSC can be realized without relying on the exotic Cooper pairing such as odd-parity superconductivity or chiral superconductivity. Thus, we do not touch theoretical proposals of unconventional Cooper pairs in TMDs 36,[44][45][46][47] .…”

“…Superconducting few-layer TMDs have been reported in recent experiments 29,34 . From the theoretical point of view, odd-parity superconductivity has been theoretically proposed 35,36 .…”