Electron-hole atomic double layers: towards high-temperature exciton condensation

Excitons, bound electron-hole pairs, in semiconductors are bosons that can form condensates. With a much smaller mass than atoms, they have been predicted to condense at a much higher temperature scale. Although the concept has been understood for more than sixty years, experimental realization of exciton condensates or superfluids has remained challenging. In this talk, I will discuss our recent efforts in creating a high-density equilibrium exciton fluid in atomic double layers made of semiconducting transition metal dichalcogenides. I will present results from both thermodynamics and transport measurements that establish high-temperature excitonic insulators. I will also discuss the physics of doped excitonic insulators that can support a Bose-Fermi mixture and an equilibrium trion fluid.