Theory for electric dipole superconductivity with an application for bilayer excitons

TL;DR

This paper develops a theoretical framework for electric dipole superconductivity in bilayer systems, predicting phenomena like the Meissner effect and Josephson effect that could directly confirm exciton superfluidity.

Contribution

It introduces a general theory for electric dipole superconductivity, deriving London and Ginzburg-Landau equations, and predicts observable effects in bilayer exciton systems.

Findings

Prediction of Meissner-type effect in electric dipole superconductors

Derivation of Josephson effect for electric dipole currents

Provides a basis for direct experimental detection of exciton superfluidity

Abstract

Exciton superfluid is a macroscopic quantum phenomenon in which large quantities of excitons undergo the Bose-Einstein condensation. Recently, exciton superfluid has been widely studied in various bilayer systems. However, experimental measurements only provide indirect evidence for the existence of exciton superfluid. In this article, by viewing the exciton in a bilayer system as an electric dipole, we provide a general theory for the electric dipole superconductivity, and derive the London-type and Ginzburg-Landau-type equations for the electric dipole superconductors. By using these equations, we discover the Meissner-type effect and the electric dipole current Josephson effect. These effects can provide direct evidence for the formation of the exciton superfluid state in bilayer systems and pave new ways to drive an electric dipole current.