Hartree-Fock study of the moiré Hubbard model for twisted bilayer transition metal dichalcogenides

Twisted bilayer transition metal dichalcogenides have emerged as important model systems for the investigation of correlated electron physics because their interaction strength, carrier concentration, band structure, and inversion symmetry breaking are controllable by device fabrication, twist angle, and, most importantly, gate voltage, which can be varied in situ. The low-energy physics of some of these materials has been shown to be described by a "moiré Hubbard model"generalized from the usual Hubbard model by the addition of strong, tunable spin-orbit coupling and inversion symmetry breaking. In this work, we use a Hartree-Fock approximation to reach a comprehensive understanding of the moiré Hubbard model on the mean-field level. We determine the magnetic and metal-insulator phase diagrams, and assess the effects of spin-orbit coupling, inversion symmetry breaking, and the tunable van Hove singularity. We also consider the spin and orbital effects of applied magnetic fields. This work provides guidance for experiments and sets the stage for beyond-mean-field calculations.