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Spectroscopy of Twisted Bilayer Graphene Correlated Insulators

Author(s): Călugăru, Dumitru; Regnault, Nicolas; Oh, Myungchul; Nuckolls, Kevin P.; Wong, Dillon; et al

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Abstract: We analytically compute the scanning tunneling microscopy (STM) signatures of integer-filled correlated ground states of the magic angle twisted bilayer graphene (TBG) narrow bands. After experimentally validating the strong-coupling approach at ±4 electrons/moiré unit cell, we consider the spatial features of the STM signal for 14 different many-body correlated states and assess the possibility of Kekulé distortion (KD) emerging at the graphene lattice scale. Remarkably, we find that coupling the two opposite graphene valleys in the intervalley-coherent (IVC) TBG insulators does not always result in KD. As an example, we show that the Kramers IVC state and its nonchiral U (4) rotations do not exhibit any KD, while the time-reversal-symmetric IVC state does. Our results, obtained over a large range of energies and model parameters, show that the STM signal and Chern number of a state can be used to uniquely determine the nature of the TBG ground state.
Publication Date: 15-Sep-2022
DOI: doi:10.1103/physrevlett.129.117602
ISSN: 0031-9007
EISSN: 1079-7114
Language: en
Type of Material: Journal Article
Journal/Proceeding Title: Physical Review Letters
Version: Author's manuscript

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