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The study of twisted bilayer graphene (TBG) is a hot topic in condensed matter physics with special focus onmagic anglesof twisting at which TBG acquires unusual properties. Mathematically, topologically non-trivial flat bands appear at those special angles. The chiral model of TBG pioneered by Tarnopolsky, Kruchkov, and Vishwanath (2019) has particularly nice mathematical properties and we survey, and in some cases, clarify, recent rigorous results which exploit them.
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Interacting Twisted Bilayer Graphene with Systematic Modeling of Structural Relaxation
Abstract Twisted bilayer graphene (TBG) has drawn significant interest due to recent experiments which show that TBG can exhibit strongly correlated behavior such as the superconducting and correlated insulator phases. Much of the theoretical work on TBG has been based on analysis of the Bistritzer-MacDonald model which includes a phenomenological parameter to account for lattice relaxation. In this work, we use a newly developed continuum model which systematically accounts for the effects of structural relaxation. In particular, we model structural relaxation by coupling linear elasticity to a stacking energy that penalizes disregistry. We compare the impact of the two relaxation models on the corresponding many-body model by defining an interacting model projected to the flat bands. We perform tests at charge neutrality at both the Hartree-Fock and Coupled Cluster Singles and Doubles (CCSD) level of theory and find the systematic relaxation model gives quantitative differences from the simplified relaxation model.
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- Award ID(s):
- 2406981
- PAR ID:
- 10612126
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Electronic Structure
- ISSN:
- 2516-1075
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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