Hubbard model physics in transition metal dichalcogenide moir\'e bands

TL;DR

This paper theoretically demonstrates that twisted transition metal dichalcogenide heterobilayers host flat moiré bands modeled by Hubbard models, with tunable parameters leading to potential exotic many-body ground states such as spin liquids and topological superconductors.

Contribution

It shows the presence of flat moiré bands in TMD heterobilayers and how their properties can be tuned to realize various correlated quantum phases.

Findings

Presence of flat moiré bands in TMD heterobilayers.

Tunable Hubbard model parameters via twist angle and dielectric environment.

Potential realization of spin liquids, quantum anomalous Hall insulators, and chiral d-wave superconductors.

Abstract

Flexible long period moir\' e superlattices form in two-dimensional van der Waals crystals containing layers that differ slightly in lattice constant or orientation. In this Letter we show theoretically that isolated flat moir\' e bands described by generalized triangular lattice Hubbard models are present in twisted transition metal dichalcogenide heterobilayers. The hopping and interaction strength parameters of the Hubbard model can be tuned by varying the twist angle and the three-dimensional dielectric environment. When the flat moir\'e bands are partially filled, candidate many-body ground states at some special filling factors include spin-liquid states, quantum anomalous Hall insulators and chiral $d$-wave superconductors.