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FRI: Friday Contributed Sessions

FRI 11: Quantum 2D-Moiré and Rhombohedral van-der-Waals Systems: Contributed Session to Symposium

FRI 11.7: Talk

Friday, September 12, 2025, 12:15–12:30, ZHG104

A Wannier approach to electronic structure in twisted van der Waals bilayers — •Ruven Hübner¹, Matthias Florian², and Alexander Steinhoff¹ — ¹Institute for Physics, Faculty V, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany — ²University of Michigan, Dept. of Electrical Engineering and Computer Science, Ann Arbor, MI, USA

Moiré structures in two-dimensional van der Waals materials offer an interesting platform to explore the interplay of quantum phenomena across vastly different length scales—from the atomic scale, on the order of Ångström, to the supercell scale, reaching up to ∼40 nm. While DFT calculations have made remarkable progress in handling large systems, they do not readily reveal the dominant mechanisms that govern the electronic structure. In fact, it seems natural to retain much of the electronic structure of the individual monolayers and treat the interlayer interaction as a relatively small perturbation. This view can be well motivated by the model of Koshino, who introduced a tight-binding framework for moiré bilayers where a simple basis transformation reveals dominant interlayer couplings in reciprocal space, enabling a significant reduction in basis states [1]. We take this approach one step further by incorporating the Wannier projection method, based on multiple DFT calculations of untwisted bilayers with different stacking configurations. Besides providing a computationally efficient model, our framework enables analytical insight into moiré band splitting within the original Brillouin zones of the monolayers. [1] Mikito Koshino 2015 New J. Phys. 17 015014

Keywords: moiré; Wannier; tight-binding; twisted; interlayer