We report two-dimensional quantum transport in SrMnBi2 single crystals. The linear energy dispersion leads to the unusual nonsaturated linear magnetoresistance since all Dirac fermions occupy the lowest Landau level in the quantum limit. The transverse magnetoresistance exhibits a crossover at a critical field B∗ from semiclassical weak-field B2 dependence to the high-field linear-field dependence. With increase in the temperature, the critical field B∗ increases and the temperature dependence of B∗ satisfies quadratic behavior which is attributed to the Landau level splitting of the linear energy dispersion. The effective magnetoresistant mobility μMR∼3400 cm2/Vs is derived. Angular dependent magnetoresistance and quantum oscillations suggest dominant two-dimensional (2D) Fermi surfaces. Our results illustrate the dominant 2D Dirac fermion states in SrMnBi2 and imply that bulk crystals with Bi square nets can be used to study low dimensional electronic transport commonly found in 2D materials like graphene.
@article{arxiv.1204.1049,
title = {Quantum transport of two-dimensional Dirac fermions in SrMnBi2},
author = {Kefeng Wang and D. Graf and Hechang Lei and S. W. Tozer and C. Petrovic},
journal= {arXiv preprint arXiv:1204.1049},
year = {2015}
}