This is not the latest version of this item. The latest version can be found here.
Excitonic density wave and spin-valley superfluid in bilayer transition metal dichalcogenide
Name
s41467-020-20802-z.pdf
Description
Published version
Size
2.19 MB
Format
Adobe PDF
Checksum (MD5)
30b38d07169982c997115443c305184e
Author(s)
Bi, Zhen
Fu, Liang
Date Issued
2021
Journal
Nature Communications
Publisher
Springer Science and Business Media LLC
Citation
Bi, Zhen and Fu, Liang. 2021. "Excitonic density wave and spin-valley superfluid in bilayer transition metal dichalcogenide." Nature Communications, 12 (1).
Version
Final published version
Abstract
Artificial moiré superlattices in 2d van der Waals heterostructures are a new venue for realizing and controlling correlated electronic phenomena. Recently, twisted bilayer WSe emerged as a new robust moiré system hosting a correlated insulator at moiré half-filling over a range of twist angle. In this work, we present a theory of this insulating state as an excitonic density wave due to intervalley electron–hole pairing. We show that exciton condensation is strongly enhanced by a van Hove singularity near the Fermi level. Our theory explains the remarkable sensitivity of the insulating gap to the vertical electric field. In contrast, the gap is weakly reduced by a perpendicular magnetic field, with quadratic dependence at low field. The different responses to electric and magnetic field can be understood in terms of pair-breaking versus non-pair-breaking effects in a BCS analog of the system. We further predict superfluid spin transport in this electrical insulator, which can be detected by optical spin injection and spatial-temporal imaging. 2
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
10.1038/S41467-020-20802-Z
