Exchange and spin-orbit proximity driven topological and transport phenomena in twisted graphene/CrI$_3$ heterostructures

Abstract

We present results of comprehensive first-principles and kp-method studies of electronic, magnetic, and topological properties of graphene on a monolayer of CrI$_3$. First, we identify a twist angle between the graphene and CrI$_3$, that positions the graphene Dirac cones within the bandgap of CrI$_3$. Then, we derive the low-energy effective Hamiltonian describing electronic properties of graphene Dirac cones. Subsequently, we examine anomalous and valley Hall conductivity and discuss possible topological phase transition from a quantum anomalous Hall insulator to a trivial insulating state, concomitant a change in the magnetic ground state of CrI$_3$. These findings highlight the potential of strain engineering in two-dimensional van der Waals heterostructures for controlling topological and magnetic phases.