Seeking the Dirac cones in the MoS2/WSe2 van der Waals heterostructure

Ab initio calculations show that the bandgap of MoS2-WSe2 heterostructures can be significantly tuned by thickness engineering, perpendicular electric fields, and forming spin-valley coupling Dirac cones at the K and K ′ valleys. The intrinsic band structure of the MoS2-WSe2 heterobilayer is found to be a direct bandgap, in which the conduction band minimum is located at the MoS2 layer, but the valence band maximum lies in the WSe2 layer, forming a type-II band alignment, which can be changed easily into type-I band alignment by applying perpendicular electric fields. The special dispersion relation like the Dirac cone and each of these band alignments have particular applications in enabling different varieties of devices.