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TT: Fachverband Tiefe Temperaturen
TT 96: 2D Materials: Stacking and heterostructures (joint session O/HL/TT)
TT 96.10: Vortrag
Freitag, 13. März 2026, 11:45–12:00, HSZ/0401
Coexisting charge density waves in twisted NbSe2 bilayers — •Christopher Tat Shun Cheung1, Zachary A. H. Goodwin2, Yixuan Han3, Jiong Lu3, Arash A. Mostofi1, and Johannes Lischner1 — 1Departments of Physics and Materials and the Thomas Young Center for Theory and Simulation of Materials, Imperial College London, London SW7 2AZ, U.K. — 2Institute for Functional Intelligent Materials, National University of Singapore, Singapore 117544, Singapore — 3Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
Twisted bilayers of semiconducting transition metal dichalcogenide (TMD) monolayers have been studied extensively. In contrast, twisted bilayers composed of metallic monolayers, such as NbSe2, remain less understood.
Monolayer NbSe2 can host different types of charge density waves (CDWs), in which the Nb atoms move away from their high-symmetry positions. In twisted bilayer NbSe2, identifying CDWs in relaxed structures is challenging because atomic relaxations occur both because of CDW formation and also because of the moiré pattern.
We have carried out large-scale first-principles calculations using density functional theory to study the moiré relaxations and CDWs in twisted bilayer NbSe2. We have developed methods for revealing the CDWs, and for locally classifying the type of CDW. We find that different types of CDWs coexist in the moiré unit cell due to the interactions with strain induced by moiré relaxations [1].
[1] Cheung et al, Nano Lett. 2024, 24, 12088-12094.
Keywords: Twisted moiré bilayers; Charge density waves; NbSe2; Symmetry broken states