Year: 2024
Type: article
Abstract: Moiré superlattices of semiconducting transition metal dichalcogenide (TMD) heterobilayers are model systems for investigating strongly correlated electronic phenomena1-12. Specifically, WSe2/WS2 moiré superlattices has emerged as a quantum simulator for the 2D extended Hubbard model1,2, which hosts fascinating correlated charge and spin physics. Experimental studies of charge transport have revealed correlated Mott insulator1,2 and generalized Wigner crystal states1, 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 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 measured spin diffusion constant, we can estimate the effective hopping amplitude t and exchange coupling J in the superlattice. Our results demonstrate opportunities for exploring novel spin physics in correlated electronic systems using TMD moiré superlattices.
Source: Nature Communications
Institutions: Lawrence Berkeley National Laboratory, University of California, Berkeley, Massachusetts Institute of Technology, University of Tennessee at Knoxville, University of California, Santa Barbara, National Institute for Materials Science, Arizona State University, Kavli Energy NanoScience Institute
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $6,790
Awards: G1197496967, G1286236842, G1286251239, G1783960089, G1867236772, CREATING AND PROBING LARGE GAP 2D TOPOLOGICAL INSULATORS FOR QUANTUM COMPUTING, G2055624445, G2133534608, G2479707703, G2584691830, G2657181000, G2920044675, G30714459, CREATING AND PROBING LARGE GAP 2D TOPOLOGICAL INSULATORS FOR QUANTUM COMPUTING, CAREER: Point Defects in Two-dimensional Material Systems: Fundamentals and New Perspectives, Spin-orbitronic devices based on 2D Rashba Janus crystals as active materials, G419881185, G4257986054, G42916606, G498139845, G5517471898, G650090426, G6664495284, G7519024414, G7524530, THE SYNTHESIS 2D JANUS VDW CRYSTALS AND NOVEL QUANTUM PHENOMENA ARISING FROM MIRROR-SYMMETRY BREAKING, G8275944008, G8316820965, Discovery and Fundamental Investigation of Emergent Phenomena in Novel 2D Magnets, Bosonic Condensation and Emergent Phenomena in 2D Janus layers and Moiré Lattices, Synthesis of high quality single crystals for sience of Boron Nitride, G8939273476, G969889393, Wafer-Scale Manufacturing of Two-Dimensional Anisotropic Nanomaterials by Chemical Vapor Deposition
OpenAlex ID: W4404741503