Eliashberg theory for dynamical screening in bilayer exciton condensation

Abstract

We study the effect of dynamical screening of interactions on the transition temperatures ($T_c$) of exciton condensation in a symmetric bilayer of quadratically dispersing electrons and holes by solving the linearized Eliashberg equations for the anomalous interlayer Green's functions. We find that $T_c$ is finite for the range of density and layer separations studied, decaying exponentially with interlayer separation. $T_c$ is suppressed well below that predicted by a Hartree Fock mean field theory with unscreened Coulomb interaction, but is above the estimates from the statically screened Coulomb interaction. Furthermore, using a diagrammatic framework, we show that the system is always an exciton condensate at zero temperature but $T_c$ is exponentially small for large interlayer separation.

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Cited by in corpus (3)

• 2D bilayer electron-hole superfluidity with unequal and anisotropic masses
• Longitudinal Josephson effect in systems with pairing of spatially separated electrons and holes
• Unconventional superconductivity mediated by exciton density wave fluctuations