  We report two-dimensional quantum transport and Dirac fermions in YbMnBi2
single crystals. YbMnBi2 is a layered material with anisotropic conductivity
and magnetic order below 290 K. Magnetotransport properties, nonzero Berry
phase and small cyclotron mass indicate the presence of quasi two dimensional
Dirac fermions. Quantum oscillations in Hall resistivity suggest the presence
of both electron and hole parts of the Fermi surface whereas the Berry phase
suggests spin-orbit coupling.
