Possible Wigner states in CrI3 heterostructures with graphene: A tight-binding model perspective

Abstract

In this study, we present an effective tight-binding model for an accurate description of the lowest energy quadruplet of a conduction band in a ferromagnetic CrX3 monolayer, tuned to the complementary density functional theory simulations. This model, based on a minimum number of chromium orbitals, captures a distinctively flat dispersion in those bands but requires taking into account hoppings beyond nearest neighbors, revealing ligand-mediated electron pathways connecting remote chromium sites. Doping of states in the lowest conduction band of CrX3 requires charge transfer, which, according to recent studies [Tenasini , ; Tseng , ; Cardoso , , can occur in graphene(G)/CrX3 heterostructures. Here, we use the detailed description of the lowest conduction band in CrI3 to show that G/CrI3/G and G/CrI3 are type-II heterostructures where light holes in graphene would coexist with heavy electrons in the magnetic layer, where the latter can be characterized by Wigner-Seitz radius rs∼25−35 (as estimated for hBN-encapsulated structures). Published by the American Physical Society 2024