Surface energy and magneto-capacitance of superconductors under electric field bias

TL;DR

This paper investigates how electric and magnetic fields influence the surface energy and magneto-capacitance of superconductors using the Ginzburg-Landau theory, revealing a capacitance jump at the surface critical field.

Contribution

It introduces a theoretical analysis of surface energy and magneto-capacitance in superconductors under electric and magnetic fields within the Ginzburg-Landau framework, including the effect of sample thickness.

Findings

Capacitance exhibits a jump at the surface critical field.

Surface energy depends on electric and magnetic fields.

Magnetic-field effects are influenced by sample thickness.

Abstract

A superconducting layer exposed to a perpendicular electric field and a parallel magnetic field is considered within the Ginzburg-Landau (GL) approach. The GL equation is solved near the surface and the surface energy is calculated. The nucleation critical field of superconducting state at the surface depends on the magnetic and electric fields. Special consideration is paid to the induced magnetic-field effect cause d by diamagnetic surface currents. The latter effect is strongly dependent on the thickness of the sample. The effective inverse capacitance determines the effective penetration depth. It is found that the capacitance exhibits a jump at the surface critical field. An experiment is suggested for determining the change in the effective capacitance of the layer.