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arXiv · 2108.02159

Competing magnetic states in transition metal dichalcogenide moiré materials

Nai Chao Hu·Allan H. MacDonald
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Abstract

Small-twist-angle transition metal dichalcogenide (TMD) heterobilayers develop isolated flat moiré bands that are approximately described by triangular lattice generalized Hubbard models [PhysRevLett.121.026402]. In this article we explore the metallic and insulating states that appear under different control conditions at a density of one-electron per moiré period, and the transitions between them. By combining fully self-consistent Hartree-Fock theory calculations with strong-coupling expansions around the atomic limit, we identify four different magnetic states and one nonmagnetic state near the model phase diagram's metal-insulator phase-transition line. Ferromagnetic insulating states, stabilized by non-local direct exchange interactions, are surprisingly prominent.

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Nai Chao Hu, Allan H. MacDonald. 2021-08-04. Competing magnetic states in transition metal dichalcogenide moiré materials. https://doi.org/10.1103/physrevb.104.214403

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