Strong surface contribution to the Nonlinear Meissner Effect

TL;DR

This paper reveals that in d-wave superconductors, surface Andreev bound states significantly influence the nonlinear Meissner effect at low temperatures, leading to a surface-dominated response with a distinct temperature dependence.

Contribution

It introduces the dominant role of surface effects in the nonlinear Meissner effect of d-wave superconductors and provides analytical and numerical insights into this phenomenon.

Findings

Surface contribution follows a 1/T^3 law with opposite sign to bulk behavior.

Crossover from bulk to surface dominance occurs at T/T_c ~ 1/sqrt(kappa).

Surface effects can be experimentally probed via intermodulation distortion.

Abstract

We demonstrate that in a d-wave superconductor the bulk nonlinear Meissner effect is dominated by a surface effect due to Andreev bound states at low temperatures. The contribution of this surface effect to the nonlinear response coefficient follows a 1/T^3 law with opposite sign compared to the bulk 1/T behavior. The cross-over from bulk dominated behavior to surface dominated behavior occurs at a temperature of T/T_c ~ 1/sqrt(kappa). We present an approximate analytical calculation, which supports our numerical calculations and provides a qualitative understanding of the effect. The effect can be probed by intermodulation distortion experiments.