Pairing transition in a double layer with interlayer Coulomb repulsion

TL;DR

This paper investigates how strong interlayer Coulomb interactions induce a novel interlayer pairing state in a double layer system, revealing duality with excitonic pairing and analyzing its transport and fluctuation properties.

Contribution

It introduces a new interlayer pairing state driven by Coulomb repulsion and explores its duality with excitonic pairing in electron-hole layers.

Findings

Interlayer pairing leads to strong current correlations.

The state exhibits both gapped and gapless fluctuation modes.

Interlayer conductivity is analyzed in the pairing regime.

Abstract

We study the effect of interlayer Coulomb interaction in an electronic double layer. Assuming that each of the layers consists of a bipartite lattice, a sufficiently strong interlayer interaction leads to an interlayer pairing of electrons with a staggered order parameter. We show that the correlated pairing state is dual to the excitonic pairing state with uniform order parameter in an electron-hole double layer. The interlayer pairing of electrons leads to strong current-current correlations between the layers. We also analyze the interlayer conductivity and the fluctuations of the order parameter, which consists of a gapped and a gapless mode.