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arXiv · 2401.12313

Eliashberg theory for dynamical screening in bilayer exciton condensation

G. J. Sreejith·Jay D. Sau·Sankar Das Sarma
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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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G. J. Sreejith, Jay D. Sau, Sankar Das Sarma. 2024-01-22. Eliashberg theory for dynamical screening in bilayer exciton condensation. https://doi.org/10.1103/physrevlett.133.056501

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