Thermodynamically Induced Transport Anomaly in Dilute Metals ZrTe$_5$ and HfTe$_5$

TL;DR

This paper explains the anomalous transport behavior in ZrTe$_5$ and HfTe$_5$ as a thermodynamic effect caused by temperature and magnetic field dependence of the chemical potential, without invoking phase transitions.

Contribution

It provides a thermodynamic model accounting for the transport anomalies in dilute metals ZrTe$_5$ and HfTe$_5$, matching experimental observations without assuming phase transitions.

Findings

Reproduces resistivity, Hall, and Seebeck coefficients in zero field.

Matches magnetoresistivity and Hall resistivity in finite magnetic fields.

Explains sign reversals and resistivity peaks through thermodynamic effects.

Abstract

A 40-year-old puzzle in transition metal pentatellurides ZrTe$_5$ and HfTe$_5$ is the anomalous peak in the temperature dependence of the longitudinal resistivity, which is accompanied by sign reverses of the Hall and Seebeck coefficients. We give a plausible explanation for these phenomena without assuming any phase transition or strong interaction effect. We show that due to intrinsic thermodynamics and diluteness of the conducting electrons in these materials, the chemical potential displays a strong dependence on the temperature and magnetic field. With that, we compute resistivity, Hall and Seebeck coefficients in zero field, and magnetoresistivity and Hall resistivity in finite magnetic fields, in all of which we reproduce the main features that are observed in experiments.