Mott domain walls: a (strongly) non-Fermi liquid state of matter

TL;DR

This paper investigates the properties of domain walls in Mott systems near the metal-insulator transition, revealing a non-Fermi liquid state dominated by resilient quasiparticles and quantum-critical fluctuations.

Contribution

It introduces a detailed analysis of domain wall matter in the Hubbard model, highlighting the emergence of resilient quasiparticles with non-Fermi liquid behavior.

Findings

Domain walls occupy significant volume fractions in Mott systems.

Transport is dominated by resilient quasiparticles with non-Fermi liquid features.

Quantum-critical fluctuations influence the properties of the domain wall regime.

Abstract

Most Mott systems display a low-temperature phase coexistence region around the metal-insulator transition. The domain walls separating the respective phases have very recently been observed both in simulations and in experiments, displaying unusual properties. First, they often cover a significant volume fraction, thus cannot be neglected. Second, they neither resemble a typical metal nor a standard insulator, displaying unfamiliar temperature dependence of (local) transport properties. Here we take a closer look at such domain wall matter by examining an appropriate unstable solution of the Hubbard model. We show that transport in this regime is dominated by the emergence of "resilient quasiparticles" displaying strong non-Fermi liquid features, reflecting the quantum-critical fluctuations in the vicinity of the Mott point.