Engineering a pure Dirac regime in ZrTe$_5$

TL;DR

This paper demonstrates how strain can be used to tune ZrTe$_5$ into a pure Dirac semimetal phase by removing trivial Fermi pockets, clarifying previous conflicting reports.

Contribution

It introduces a method to control the band structure of ZrTe$_5$ via strain, achieving a pure Dirac regime and mapping the structural conditions needed.

Findings

Strain effectively removes trivial pockets from ZrTe$_5$ near the Fermi level.

A specific Van der Waals gap range yields a pure Dirac semimetal phase.

The results reconcile previous conflicting experimental reports.

Abstract

Real-world topological semimetals typically exhibit Dirac and Weyl nodes that coexist with trivial Fermi pockets. This tends to mask the physics of the relativistic quasiparticles. Using the example of ZrTe5, we show that strain provides a powerful tool for in-situ tuning of the band structure such that all trivial pockets are pushed far away from the Fermi energy, but only for a certain range of Van der Waals gaps. Our results naturally reconcile contradicting reports on the presence or absence of additional pockets in ZrTe$_5$, and provide a clear map of where to find a pure three-dimensional Dirac semimetallic phase in the structural parameter space of the material.