Collapse of Landau levels in semi-Dirac materials

Two-dimensional semi-Dirac models describe a family of novel materials that have anisotropic dispersion with a relativistic-type spectrum along one of the spatial directions and nonrelativistic along another. In the present paper we perform a detailed analysis of the collapse of Landau levels for such models in a perpendicular magnetic field and in-plane electric field by using a semiclassical approach. The anisotropic nature of semi-Dirac dispersion manifests itself in the possibility of a Landau level collapse for only one of the electric field directions. In addition, the topological transition with merging Dirac cones has its own distinct features in a Landau level collapse.