Abstract
We report two-dimensional Dirac fermions and quantum magnetoresistance in single crystals of CaMnBi. The nonzero Berry's phase, small cyclotron resonant mass, and first-principles band structure suggest the existence of the Dirac fermions in Bi square nets. The in-plane transverse magnetoresistance exhibits a crossover at a critical field from semiclassical weak-field dependence to the high-field unsaturated linear magnetoresistance ( in 9 T at 2 K) due to the quantum limit of the Dirac fermions. The temperature dependence of satisfies quadratic behavior, which is attributed to the splitting of linear energy dispersion in high field. Our results demonstrate the existence of two-dimensional Dirac fermions in CaMnBi with Bi square nets.
- Received 30 December 2011
DOI:https://doi.org/10.1103/PhysRevB.85.041101
©2012 American Physical Society