A Self-Consistent Microscopic Theory of Surface Superconductivity

TL;DR

This paper develops a self-consistent microscopic theory for surface superconductivity in type-II superconductors, revealing detailed electronic structures and oscillations near the surface that differ from traditional Ginzburg-Landau predictions.

Contribution

It introduces a self-consistent microscopic approach using Bogoliubov-de Gennes equations to analyze surface superconductivity, highlighting the importance of Friedel oscillations and magnetic edge states.

Findings

Pronounced Friedel oscillations in the pair potential near the surface

Significant depletion of the local density of states near the Fermi energy

Surface electronic structure differs markedly from Ginzburg-Landau theory predictions

Abstract

The electronic structure of the superconducting surface sheath in a type-II superconductor in magnetic fields $H_{c2}<H<H_{c3}$ is calculated self-consistently using the Bogoliubov-de Gennes equations. We find that the pair potential $\Delta(x)$ exhibits pronounced Friedel oscillations near the surface, in marked contrast with the results of Ginzburg-Landau theory. The role of magnetic edge states is emphasized. The local density of states near the surface shows a significant depletion near the Fermi energy due to the development of local superconducting order. We suggest that this structure could be unveiled by scanning-tunneling microscopy studies performed near the edge of a superconducting sample.