Electronic Structure and Correlations in Twisted Multilayer Graphene and Related Layered Materials

In the past decade the field of twisted multilayer graphene and other layered materials, like the transition-metal dichalcogenide family, has blossomed to the point of being referred with its own term, ``twistronics'' [1]. New arrangements, including twisted n-layers (n=3,4,...), mixed layers, and multilayers of regular few-layer structures, are being studied experimentally and they are revealing ever richer behavior. We review theoretical investigations of some representative systems [2], starting with the iconic twisted bilayer graphene near the magic angle. Our work is based on first-principles tight-biding hamiltonians and includes atomic relaxation though the configuration space approach. A recent focus has been on deriving realistic representations of single-particle states for few-band hamiltonians and how those can be employed in studying many-body physics related to Mott insulator behavior, superconductivity and other manifestations of correlated electronic states [3].<br/>Work supported by Army Research Office under Cooperative Agreement Number W911NF-21-2-0147 and by a grant from the Simons Foundation Award no. 896626.<br/><br/>[1] S. Carr, D. Massatt, S. Fang, P. Cazeaux, M. Luskin, and E. Kaxiras, Phys. Rev. B. <b>95</b>, 075420 (2017)<br/>[2] S. Carr, S. Fang, E. Kaxiras, Nature Reviews – Materials, https://doi.org/10.1038/s41578-020-0214-0<br/>[3] D. Bennett, D. T. Larson, L. Sharma, S. Carr, and E. Kaxiras, Phys. Rev. B 109, 155422 (2024)