Fulde-Ferrell-Larkin-Ovchinnikov superconductors near a surface

TL;DR

This paper investigates the unique surface behaviors of Fulde-Ferrell-Larkin-Ovchinnikov superconductors, revealing deformed order parameters and unusual magnetic responses near surfaces, including anti-screening effects and a peculiar surface critical field dependence.

Contribution

It provides a detailed analysis of surface effects in FFLO superconductors, highlighting phenomena not observed in conventional superconductors.

Findings

Deformation of the order parameter near the surface

Presence of anti-screening and over-screening effects

Unusual temperature dependence of the surface critical field Hc3

Abstract

We show that the behaviour of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconductors near a surface is considerably different from the usual case. The order parameter of the FF state is strongly deformed near the surface, which leads to a number of unusual features in the linear magnetic response, such as "anti-screening" or "over-screening" of the applied field. In a fully isotropic FF case, the Meissner effect is still present, despite the vanishing of the transverse superfluid density in the bulk. We also calculate the surface critical field Hc3, which exhibits a peculiar temperature dependence.