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TT: Fachverband Tiefe Temperaturen
TT 88: 2D Materials and Heterostuctures: (Twisted) Bilayers (joint session HL/TT)
TT 88.2: Talk
Friday, March 22, 2024, 09:45–10:00, EW 201
Twist disorder in tWSe2: Insights from Lateral Force Microscopy and Raman Spectroscopy — •Nicolai-Leonid Bathen1, Rami Dana2, Hendrik Lambers1, Nihit Saigal1, Julian Klein2, Frances M. Ross2, and Ursula Wurstbauer1 — 1University of Münster, Münster, Germany — 2Massachusetts Institute of Technology, Cambridge, MA, United States
Bilayers of twisted transition metal dichalcogenides (TMDCs) form moiré hybridized lattices resulting in moiré minibands [1] which leads to the capability to host correlated quantum phases [2] and to simulate Mott-Hubbard physics [3]. These properties vary strongly with the local twist angle configuration due to changes in the moiré cell size, symmetry and long-range disorder. Here we unravel the formation of moiré lattices and local disorder in the twist angle in twisted WSe2 homo-bilayers (tWSe2) by lateral force microscopy in ambient providing atomic resolution. We studied several tWSe2 bilayers with a large variety in the nominal twist angle of 3∘ to 11∘ and find a surprisingly large variation in twist angle up to 1∘ within less than a micrometer distance. We contrast those findings with low-frequency Raman measurements sensitive to interlayer coupling and we will discuss consequences of the local twist disorder for collective inter-moiré band excitations studied by resonant inelastic light scattering [1].
[1] N. Saigal et al., arXiv 2310 14417 (2023) [2] N. P. Wilson et al., Nature 599, 383-392 (2021) [3] S. Ryee and T. O. Wehling, Nano Lett. 23 (2), 573-579 (2023) [4] Y. Song and E. Meyer, ACS Langmuir 39, 15409 (2023)
Keywords: 2D materials; Van der Waals heterostructures; Transition metal dichalcogenides; Raman spectroscopy; Twistronics