Extremely large magnetoresistance and high-density Dirac-like fermions in ZrB2

TL;DR

This study reveals that ZrB2 is a topological nodal-line semimetal with extremely large magnetoresistance, high-density Dirac-like fermions, and unique transport properties explained by a two-band model.

Contribution

It provides detailed transport measurements of ZrB2, demonstrating its topological nature and high-density Dirac-like fermions, which are novel findings for this material.

Findings

ZrB2 exhibits extremely large magnetoresistance.

Electrons have high density and nontrivial Berry phase.

Transport behavior is explained by a two-band model with perfect electron-hole compensation.

Abstract

We report the detailed study on transport properties of ZrB2 single crystal, a predicted topological nodal-line semimetal. ZrB2 exhibits extremely large magnetoresistance as well as field-induced resistivity upturn and plateau. These behaviors can be well understood by the two-band model with the perfect electron - hole compensation and high carrier mobilities. More importantly, the electrons with small effective masses and nontrivial Berry phase have significantly high density when compared to those in known topological semimetals. It strongly suggests that ZrB2 hosts Dirac-like nodal-line fermions.