Electron-hole asymmetry, Dirac fermions, and quantum magnetoresistance in BaMnBi2

TL;DR

This paper reports the discovery of Dirac fermions and quantum magnetoresistance in BaMnBi2, revealing complex electron-hole behavior and anisotropic transport in this layered material.

Contribution

It provides the first evidence of Dirac fermions in BaMnBi2 through magnetotransport measurements and band structure calculations, highlighting electron-hole asymmetry.

Findings

Presence of Dirac fermions indicated by Berry phase and band structure

Coexistence of electron and hole pockets at the Fermi level

Highly anisotropic conductivity and quantum oscillations

Abstract

We report two-dimensional quantum transport and Dirac fermions in BaMnBi2 single crystals. BaMnBi2 is a layered bad metal with highly anisotropic conductivity and magnetic order below 290 K. Magnetotransport properties, nonzero Berry phase, small cyclotronmass, and the first-principles band structure calculations indicate the presence of Dirac fermions in Bi square nets. Quantum oscillations in the Hall channel suggest the presence of both electron and hole pockets, whereas Dirac and parabolic states coexist at the Fermi level.