Holographic Superconductors from Einstein-Maxwell-Dilaton Gravity

TL;DR

This paper constructs holographic superconductors using Einstein-Maxwell-dilaton gravity, analyzing phase transitions and conductivity properties, revealing novel low-frequency behavior depending on model parameters.

Contribution

It introduces a generalized holographic superconductor model with adjustable couplings, exploring how these parameters affect phase transitions and conductivity features.

Findings

Critical temperature for second order phase transition identified.

Conductivity exhibits a Drude Peak at low frequencies for certain parameters.

Model interpolates between minimal and novel superconductor behaviors.

Abstract

We construct holographic superconductors from Einstein-Maxwell-dilaton gravity in 3+1 dimensions with two adjustable couplings $\alpha$ and the charge $q$ carried by the scalar field. For the values of $\alpha$ and $q$ we consider, there is always a critical temperature at which a second order phase transition occurs between a hairy black hole and the AdS RN black hole in the canonical ensemble, which can be identified with the superconducting phase transition of the dual field theory. We calculate the electric conductivity of the dual superconductor and find that for the values of $\alpha$ and $q$ where $\alpha/q$ is small the dual superconductor has similar properties to the minimal model, while for the values of $\alpha$ and $q$ where $\alpha/q$ is large enough, the electric conductivity of the dual superconductor exhibits novel properties at low frequencies where it shows a "Drude Peak" in the real part of the conductivity.