Strange metal crossover in the doped holographic superconductor

TL;DR

This paper investigates a holographic superconductor model with fermions, revealing a doping-dependent crossover from strange metal behavior to Fermi liquid characteristics, mirroring high-temperature superconductor phase diagrams.

Contribution

It introduces fermions into a holographic superconductor model and analyzes the fermionic spectral functions to identify a doping-driven crossover.

Findings

Crossover from strange metal to Fermi liquid with increasing doping

Critical doping for long-lived excitations increases with temperature

Phase diagram resembles that of high-temperature superconductors

Abstract

In a recent paper, Kiritsis and Li presented a holographic model to study the competition between different orders at finite doping in holographic superconductors. In the present work, we introduce fermions into such model and study the fermionic spectral functions in the normal phase at zero and finite temperatures. Combining analytic and numerical methods, we found that there is a crossover from a strange metal with short lived excitations at small doping, into a Fermi liquid with well defined quasiparticles at large doping. The critical doping at which excitations becomes long lived increases with temperature. The emerging phase diagram is qualitatively similar to that of High Temperature Superconductors.