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Fractionalization in Fractional Correlated Insulating States at n±1/3 Filled Twisted Bilayer Graphene

Cornell Affiliated Author(s)

Author

D. Mao
K. Zhang
E.-A. Kim

Abstract

Fractionalization without time-reversal symmetry breaking is a long-sought-after goal in the study of correlated phenomena. The earlier proposal of correlated insulating states at n±1/3 filling in twisted bilayer graphene and recent experimental observations of insulating states at those fillings strongly suggest that moiré graphene systems provide a new platform to realize time-reversal symmetric fractionalized states. However, the nature of fractional excitations and the effect of quantum fluctuation on the fractional correlated insulating states are unknown. We show that excitations of the fractional correlated insulator phases in the strong coupling limit carry fractional charges and exhibit fractonic restricted mobility. Upon introduction of quantum fluctuations, the resonance of "lemniscate"structured operators drives the system into quantum lemniscate liquid (QLL) or quantum lemniscate solid (QLS). We find an emergent U(1)×U(1) 1-form symmetry unifies distinct motions of the fractionally charged excitations in the strong coupling limit and in the QLL phase, while providing a new mechanism for fractional excitations in two dimensions. We predict emergent Luttinger liquid behavior upon dilute doping in the strong coupling limit due to restricted mobility and discuss implications at a general n±1/3 filling. © 2023 American Physical Society.

Date Published

Journal

Physical Review Letters

Volume

131

Issue

10

ISBN Number

00319007 (ISSN)

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85172257757&doi=10.1103%2fPhysRevLett.131.106801&partnerID=40&md5=3b1cf18ba5d0be1ac3ba4c2a3c924792

DOI

10.1103/PhysRevLett.131.106801

Alternate Journal

Phys Rev Lett

Group (Lab)

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