Dynamical exciton condensation in nonequilibrium electron-hole bilayers

Recent experiments have realized steady-state electrical injection of interlayer excitons in electron-hole bilayers by applying a large bias voltage. In the ideal case in which interlayer tunneling is negligibly weak, the system is in quasi-equilibrium with a reduced effective band gap. Interlayer tunneling introduces a current and leads to nonequilibrium physics. In this talk I will describe a nonequilibrium field theory of interlayer excitons in biased electron-hole bilayers and show that interlayer tunneling drives the system out of equilibrium. In the large bias, weak tunneling limit, we find that p-wave interlayer tunneling reduces the effective band gap and increases the effective temperature for intervalley excitons. I will discuss nonequilibrium effects on the critical behavior at the transition, as well as possible experimental implications of our results for InAs/GaSb quantum wells and transition metal dichalcogenide bilayers.