Shot noise in a phenomenological model of a marginal Fermi liquid

TL;DR

This paper models shot noise in a marginal Fermi liquid to explain the observed vanishing shot noise in strange metals, revealing how impurity scattering influences noise levels and aligning with experimental findings.

Contribution

It introduces a phenomenological model of a marginal Fermi liquid to analyze shot noise behavior, connecting theoretical predictions with experimental observations.

Findings

Shot noise vanishes in the diffusive regime of the MFL model.

Adding impurity scattering increases shot noise levels.

Thermal noise remains constant, independent of temperature and voltage.

Abstract

The strange metal is a mysterious non-Fermi liquid which shows linear-in-$T$ resistivity behavior at finite temperatures, and, as found in recent experiment, vanishingly small shot noise in the linear-in-$T$ regime. Here, we investigate the shot noise of a strange metal based on a phenomenological model of marginal Fermi liquid (MFL), where fermions couple to some collective boson mode, leading to $T$-linear scattering rate at finite $T$. It is found that in the diffusive regime where the MFL scattering length is small compared to the system size, the shot noise vanishes, and the thermal noise becomes a temperature- and voltage-independent constant. Introducing additional impurity scattering increases the shot noise, and is probably consistent with the current experiment.