Te Vacancy-Driven Anomalous Transport in ZrTe$_5$ and HfTe$_5$

TL;DR

This study uses first-principles calculations to show that tellurium vacancies significantly influence the electronic structure and anomalous transport properties of ZrTe$_{5}$ and HfTe$_{5}$, shedding light on their potential chiral anomaly signatures.

Contribution

It reveals how Te vacancies alter the electronic structure and transport properties, providing new insights into the microscopic mechanisms behind anomalous transport in these materials.

Findings

Te vacancies induce local electronic structure changes near the Fermi level.

Vacancies act as a source of effective compressive strain.

Results help explain previously elusive spectroscopic and transport measurements.

Abstract

In the search for experimental signatures of quantum anomalies, the layered Dirac materials ZrTe$_{5}$ and HfTe$_{5}$ have received much attention for potentially hosting a chiral anomaly. These materials exhibit a negative longitudinal magnetoresistance (NLMR) that is taken as a signature of broken chiral symmetry. The anomalous transport properties of ZrTe$_{5}$ and HfTe$_{5}$ are known to strongly correlate with the presence of Te vacancies, prompting questions as to the microscopic mechanism driving the NLMR. In this work, the effect of Te vacancies on the electronic structure of ZrTe$_{5}$ and HfTe$_{5}$ is investigated via first-principles calculations to garner insight into how they may modulate the transport properties of these materials. While Te vacancies act as a source of effective compressive strain, they also produce local changes to the electronic structure that cannot be explained simply as volume effects. The reorganization of the electronic structure near the Fermi energy indicates that Te vacancies can rationalize both spectroscopic and transport measurements that have remained elusive in prior first-principles studies. These results show that Te vacancies contribute, at least in part, to the anomalous transport properties of ZrTe$_{5}$ and HfTe$_{5}$ and offer a path towards understanding the possibility of a chiral anomaly in these materials.