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Moiré superlattices of semiconducting transition metal dichalcogenide (TMD) heterobilayers are model systems for investigating strongly correlated electronic phenomena [1-12]. Specifically, WSe2/WS2 moiré superlattices have emerged as quantum simulators for the 2D extended Hubbard model [1, 2], which hosts fascinating correlated charge and spin physics. Experimental studies of charge transport have revealed correlated Mott insulator [1, 2] and generalized Wigner crystal states [1], but spin transport of the moiré heterostructure has not yet been explored. Here, we use spatial- and temporal-resolved circular dichroism spectroscopy to directly image the spin transport as a function of carrier doping and temperature in WSe2/WS2 moiré heterostructures. We demonstrate temperature and doping dependent spin transport in the moiré superlattice: we observe diffusive spin transport at all hole concentrations at 11 Kelvin, including the Mott insulator at one hole per moiré unit cell, where charge transport is strongly suppressed. At elevated temperatures the spin diffusion constant remains unchanged at the Mott insulator state, but it increases significantly at finite doping away from the Mott state. The doping- and temperature-dependent spin transport can be qualitatively understood using a t-J model, where spins can move via hopping of spin-carrying charges and via the exchange interaction. From the spin diffusion constant, we can estimate the effective kinetic tunneling energy (t) and exchange energies (J) in the superlattice. Our results demonstrate opportunities for exploring novel spin physics in correlated electronic systems using TMD moiré superlattices.

権利情報:

• Creative Commons BY Attribution 4.0 International
  

キーワード: Moiré superlattices, spin transport, WSe2/WS2

刊行年月日: 2024-11-26

出版者: Springer Science and Business Media LLC

掲載誌:

• Nature Communications (ISSN: 20411723) vol. 15 issue. 1 10252

研究助成金:

• U.S. Department of Energy DE-AC02-05-CH11231

原稿種別: 出版者版 (Version of record)

MDR DOI:

公開URL: https://doi.org/10.1038/s41467-024-54633-z

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更新時刻: 2025-02-06 12:30:44 +0900

MDRでの公開時刻: 2025-02-06 12:30:44 +0900