Impact of the electric field on superconductivity in Bose-Einstein Condensation regime

TL;DR

This paper demonstrates that applying an electric field can induce superconductivity in the Bose-Einstein Condensation regime, effectively raising the critical temperature and enabling electric field control of the superconducting transition.

Contribution

It introduces a time-dependent Ginzburg-Landau model showing electric field-induced enhancement of superconductivity in the BEC regime, revealing a method to identify and manipulate this regime.

Findings

Electric field increases the superconducting critical temperature within the BEC regime.

An electric field can induce a transition to superconductivity at arbitrary temperatures between T_{sc} and T^*.

Existence of a critical electric field where T^* equals the electric-field-induced critical temperature.

Abstract

In the strong coupling Bose-Einstein Condensation (BEC) regime the superconductors have two characteristic temperatures: $T^*$- onset of fermion pairing and $T_{sc}$- onset of superconductivity, such that $T_{sc}<T^*$. In the present article, we consider time dependent Ginzburg-Landau theory of superconductors with slab geometry and show that applied electric field, in the temperature interval $(T_{sc},T^*)$, Bose condenses the Cooper pairs thereby increasing the superconductor critical temperature $T^E_{sc}>T_{sc}$. Important consequence is the fact that arbitrary temperature within the interval ($T_{sc},T^*$) is a critical temperature of superconductor transition if an appropriate electric field is applied. This means that if we set the temperature of the system within the above mentioned interval and increase the applied electric field the system undergoes an electric field induced transition to superconductor. We also show the existence of critical value of the applied electric field at which $T^*=T^E_{sc}$. This means that although the system is in BEC regime, away from the BCS one, we can apply an electric field that moves the system to a state with $T^E_{sc}=T^*$, characteristic of BCS regime. The results indicate that applied electric field experiments are a suitable tool to identify the BEC regime of the superconductors. The experiment can determine $T^*$ as a temperature below which the electric field Bose condenses the Cooper pairs, while above it the electrons screen the field and it cannot penetrate.