Quantum oscillations and Dirac dispersion in the BaZnBi2 semimetal guaranteed by local Zn vacancy order

TL;DR

This study reports the discovery of a new Dirac semimetal candidate, BaZnBi2, which exhibits quantum oscillations, Dirac dispersions, and non-trivial Berry phases, facilitated by unique local Zn vacancy order.

Contribution

It introduces BaZnBi2 as a novel non-magnetic Dirac semimetal with unique vacancy ordering enabling quantum oscillation observations.

Findings

BaZnBi2 shows small cyclotron mass and high quantum mobility.

Three Dirac dispersions observed by ARPES and confirmed by calculations.

Local Zn vacancy order is crucial for quantum oscillation detection.

Abstract

We have synthesized single crystals of Dirac semimetal candidates AZnBi2 with A=Ba and Sr. In contrast to A=Sr, the Ba material displays a novel local Zn vacancy ordering, which makes the observation of quantum oscillations in out-of-plane magnetic fields possible. As a new Dirac semimetal candidate, BaZnBi2 exhibits small cyclotron electron mass, high quantum mobility, and non-trivial Berry phases. Three Dirac dispersions are observed by ARPES and identified by first- principles band-structure calculations. Compared to AMn(Bi/Sb)2 systems which host Mn magnetic moments, BaZnBi2 acts as non-magnetic analogue to investigate the intrinsic properties of Dirac fermions in this structure family.