Massive Dirac fermions in layered BaZnBi$_2$

TL;DR

This study investigates the electronic structure of layered BaZnBi$_2$ using ARPES and DFT, revealing the absence of Dirac fermions and showing that the material hosts trivial, massive fermions with linear dispersive bands near the Fermi level.

Contribution

The paper provides the first detailed ARPES and DFT analysis showing BaZnBi$_2$ lacks Dirac states and hosts trivial, massive fermions, clarifying its electronic properties.

Findings

No evidence of Dirac states in BaZnBi$_2$

Spin-orbit interaction gaps out band crossing points

Presence of linear dispersive bands near Fermi level

Abstract

Using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) we study the electronic structure of layered BaZnBi$_2$. Our experimental results show no evidence of Dirac states in BaZnBi$_2$ originated either from the bulk or the surface. The calculated band structure without spin-orbit interaction shows several linear dispersive band crossing points throughout the Brillouin zone. However, as soon as the spin-orbit interaction is turned on, the band crossing points are significantly gapped out. The experimental observations are in good agreement with our DFT calculations. These observations suggest that the Dirac fermions in BaZnBi$_2$ are trivial and massive. We also observe experimentally that the electronic structure of BaZnBi$_2$ comprises of several linear dispersive bands in the vicinity of Fermi level dispersing to a wider range of binding energy.