Plasmon Mediated Superconductivity in Asymmetric Electron-Hole Bilayers

We consider equal-density, mass-asymmetric electron-hole bilayers as a platform to study various quantum phases and their transitions. With interlayer distance and independently tunable density parameters in both layers, the system has a rich three-dimensional phase space. The interplay between kinetic energy and the Coulomb interaction gives rise to liquid, crystal, and condensate phases, as well as a mixed liquid-crystal phase analogous to an alkali metal. Motivated by metallic hydrogen, we analytically predict that this mixed phase will display BCS-type superconductivity mediated by electron-plasmon interactions over a range of experimentally accessible parameters and at high temperatures. Such mass-asymmetric bilayer systems could experimentally be realized in TMD or mixed TMD-graphene heterostructures.