Nucleation of superconductivity under rapid cycling of electric field

TL;DR

This paper investigates how high frequency oscillating electric fields influence the nucleation of superconductivity, showing that such fields enhance both bulk and surface critical fields, with a greater effect at the surface.

Contribution

It introduces a theoretical analysis using TDLG and effective Hamiltonian approaches to quantify electric field effects on superconducting nucleation, highlighting a larger impact on surface nucleation.

Findings

Oscillating electric fields increase critical nucleation fields ($H_{c_2}$ and $H_{c_3}$).

Surface nucleation field ($H_{c_3}$) is more significantly enhanced than bulk ($H_{c_2}$).

Theoretical results agree with exact undriven system results.

Abstract

The effect of an externally applied high frequency oscillating electric field on the critical nucleation field of superconductivity in the bulk as well as at the surface of a superconductor is investigated in details in this work. Starting from the linearized time dependent Ginzburg-Landau (TDLG) theory and using the variational principle we have shown the analogy between a quantum harmonic oscillator with that of the nucleation of superconductivity in bulk and a quantum double oscillator with that of the nucleation at the surface of a finite sample. The effective Hamiltonian approach of Cook {\it et al} \cite{cook} is employed to incorporate the effect of an externally applied highly oscillating electric field. The critical nucleation field ratio is also calculated from the ground state energy method. The results obtained from these two approximated theories agree very well with the exact results for the case of undriven system which establishes the validity of these two approximated theories. It is observed that the highly oscillating electric field actually increases the bulk critical nucleation field ($H_{c_2}$) as well as the surface critical nucleation field ($H_{c_3}$) of superconductivity as compared to the case of absence of electric field ($\varepsilon_0=0$). But the externally applied rapidly oscillating electric field accentuates the surface critical nucleation field more than the bulk critical nucleation field i.e. the increase of $H_{c_3}$ is 1.6592 times larger than that of $H_{c_2}$.