Spectroscopy of Twisted Bilayer Graphene Correlated Insulators

Dumitru Cǎlugǎru, Nicolas Regnault, Myungchul Oh, Kevin P. Nuckolls, Dillon Wong, Ryan L. Lee, Ali Yazdani, Oskar Vafek, B. Andrei Bernevig

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

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.

Original languageEnglish (US)
Article number117602
JournalPhysical review letters
Volume129
Issue number11
DOIs
StatePublished - Sep 9 2022

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Fingerprint

Dive into the research topics of 'Spectroscopy of Twisted Bilayer Graphene Correlated Insulators'. Together they form a unique fingerprint.

Cite this