Holographic superconductivity from higher derivative theory

TL;DR

This paper develops a 6-derivative holographic superconductor model in 4D, revealing how higher derivative corrections influence critical temperature, energy gap, and Homes' law, with potential implications for high-temperature superconductors.

Contribution

It introduces a novel 6-derivative holographic superconductor model and analyzes the effects of higher derivative corrections on phase transition properties.

Findings

Critical temperature decreases with coupling parameter $oldsymbol{\gamma_1}$.

Wider superconducting energy gap compared to 4-derivative models.

Homes' law constant can match experimental values within certain parameter ranges.

Abstract

We construct a $6$ derivative holographic superconductor model in the $4$-dimensional bulk spacetimes, in which the normal state describes a quantum critical (QC) phase. The phase diagram $(\gamma_1,\hat{T}_c)$ and the condensation as the function of temperature are worked out numerically. We observe that with the decrease of the coupling parameter $\gamma_1$, the critical temperature $\hat{T}_c$ decreases and the formation of charged scalar hair becomes harder. We also calculate the optical conductivity. An appealing characteristic is a wider extension of the superconducting energy gap, comparing with that of $4$ derivative theory. It is expected that this phenomena can be observed in the real materials of high temperature superconductor. Also the Homes' law in our present models with $4$ and $6$ derivative corrections is explored. We find that in certain range of parameters $\gamma$ and $\gamma_1$, the experimentally measured value of the universal constant $C$ in Homes' law can be obtained.