Correlated electronic phases in twisted bilayer transition metal dichalcogenides

In narrow electron bands in which the Coulomb interaction energy becomes comparable to the bandwidth, interactions can drive new quantum phases. Such flat bands in twisted graphene-based systems result in correlated insulator, superconducting and topological states. Here we report evidence of low-en...

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Published in:Nature materials Vol. 19; no. 8; pp. 861 - 866
Main Authors: Wang, Lei, Shih, En-Min, Ghiotto, Augusto, Xian, Lede, Rhodes, Daniel A., Tan, Cheng, Claassen, Martin, Kennes, Dante M., Bai, Yusong, Kim, Bumho, Watanabe, Kenji, Taniguchi, Takashi, Zhu, Xiaoyang, Hone, James, Rubio, Angel, Pasupathy, Abhay N., Dean, Cory R.
Format: Journal Article
Language:English
Published: London Nature Publishing Group UK 01.08.2020
Nature Publishing Group
Springer Nature - Nature Publishing Group
Subjects:
639/766/119/1000/1018
639/925/927/1007
Bandwidths
Bilayers
Biomaterials
Chalcogenides
Chemistry
Chemistry and Materials Science
Condensed Matter Physics
Correlation analysis
Energy
Graphene
Materials Science
Nanotechnology
Optical and Electronic Materials
Phases
Physics
Signatures
Superconductivity
Transition metal compounds
Unit cell
ISSN:1476-1122, 1476-4660, 1476-4660
Online Access:Get full text
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Summary:In narrow electron bands in which the Coulomb interaction energy becomes comparable to the bandwidth, interactions can drive new quantum phases. Such flat bands in twisted graphene-based systems result in correlated insulator, superconducting and topological states. Here we report evidence of low-energy flat bands in twisted bilayer WSe 2 , with signatures of collective phases observed over twist angles that range from 4 to 5.1°. At half-band filling, a correlated insulator appeared that is tunable with both twist angle and displacement field. At a 5.1° twist, zero-resistance pockets were observed on doping away from half filling at temperatures below 3 K, which indicates a possible transition to a superconducting state. The observation of tunable collective phases in a simple band, which hosts only two holes per unit cell at full filling, establishes twisted bilayer transition metal dichalcogenides as an ideal platform to study correlated physics in two dimensions on a triangular lattice. Tunable correlated states are observed in twist bilayer WSe 2 over a range of twist angles, with signatures of superconductivity for a twist of 5.1°.
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SC0019443
USDOE Office of Science (SC)
ISSN:1476-1122
1476-4660
1476-4660
DOI:10.1038/s41563-020-0708-6