The coexistence of Dirac cones and flat band in the twisted WSe2/VSe2 moiré superlattice

The transition metal dichalcogenide twisted superlattices have received widespread attention due to their novel physical properties. Here, the electronic properties of twisted WSe2/VSe2 heterostructure at θ = 60°, 21.79° and 13.17° were studied with DFT + U based on the first-principles calculation. The results show that the WSe2/VSe2 heterostructure moiré superlattice at 13.17° angle appears Dirac cones and a flat band near the Fermi level. The Dirac cones with a band gap of approximately 5.93 meV centered at the K and K’ point in the Brillouin zone. Simultaneously, a flat band at about 65 meV below the Fermi level with a bandwidth as small as 2.86 meV is found. The high density of states of this flat band may give rise to a superconducting signal similar to twisted graphene.