Building a Holographic Superconductor with Higher-derivative Couplings

TL;DR

This paper explores a holographic superconductor model with higher-derivative couplings, revealing how these couplings influence critical temperatures, droplet solutions, and energy gaps under magnetic fields.

Contribution

It introduces a higher-derivative coupling between the gauge field and scalar in holographic superconductors, analyzing its effects on phase transition properties.

Findings

Critical temperature decreases with positive coupling ta>0 in magnetic fields.

Critical temperature increases with ta>0 in weak magnetic fields.

Energy gap is larger for negative ta<0 than in the conventional case.

Abstract

We discuss the gravitational dual of a holographic superconductor consisting of a U(1) gauge field, a complex scalar field coupled to a charged AdS black hole and a higher-derivative coupling between the U(1) gauge field and the scalar with coupling constant \eta. In the presence of a magnetic field, the system possesses localized spatially dependent droplet solutions which, in the low temperature limit, have smaller critical temperature for \eta>0 than the droplet solutions without the interaction term (\eta=0). In the weak magnetic field limit, the opposite behavior is observed: the critical temperature increases as we increase \eta. We also calculate the energy gap in the probe limit and find that it is larger for \eta<0 than the energy gap in the conventional case (\eta=0).