Striped instability of a holographic Fermi-like liquid

TL;DR

This paper investigates the instability of a holographic Fermi-like liquid in 2+1 dimensions, revealing a transition to an inhomogeneous phase driven by a Maxwell-axion mechanism and analyzing zero sound behavior at finite temperature.

Contribution

It introduces a holographic model showing a density-dependent instability leading to a modulated phase, and explores zero sound dynamics at non-zero temperature.

Findings

System becomes unstable above a critical density.

Inhomogeneous modulated phase emerges.

Zero sound persists at finite temperature.

Abstract

We consider a holographic description of a system of strongly-coupled fermions in 2+1 dimensions based on a D7-brane probe in the background of D3-branes. The black hole embedding represents a Fermi-like liquid. We study the excitations of the Fermi liquid system. Above a critical density which depends on the temperature, the system becomes unstable towards an inhomogeneous modulated phase which is similar to a charge density and spin wave state. The essence of this instability can be effectively described by a Maxwell-axion theory with a background electric field. We also consider the fate of zero sound at non-zero temperature.