Pomeranchuk Instability in a non-Fermi Liquid from Holography

TL;DR

This paper uses holographic duality to model Pomeranchuk instability in non-Fermi liquids, showing spontaneous Fermi surface distortion and anisotropic spectral weight, revealing non-Fermi liquid behavior persists through the transition.

Contribution

It introduces a holographic model with a neutral spin-two field to describe Fermi surface distortion and anisotropy in strongly interacting fermionic systems.

Findings

Fermi surfaces spontaneously distort and become anisotropic.

Low-lying fermionic excitations exhibit non-Fermi liquid behavior.

Spectral weight varies with angle and can vanish in certain directions.

Abstract

The Pomeranchuk instability, in which an isotropic Fermi surface distorts and becomes anisotropic due to strong interactions, is a possible mechanism for the growing number of experimental systems which display transport properties that differ along the $x$ and $y$ axes. We show here that the gauge-gravity duality can be used to describe such an instability in fermionic systems. Our holographic model consists of fermions in a background which describes the causal propagation of a massive neutral spin-two field in an asymptotically AdS spacetime. The Fermi surfaces in the boundary theory distort spontaneously and become anisotropic once the neutral massive spin-two field develops a normalizable mode in the bulk. Analysis of the fermionic correlators reveals that the low-lying fermionic excitations are non-Fermi liquid-like both before and after the Fermi surface shape distortion. Further, the spectral weight along the Fermi surface is angularly dependent and can be made to vanish along certain directions.