Bionic fractionalization in the trimer model of twisted bilayer graphene

Abstract Recent experiments on twisted van der Waals materials, inspired our study of a simplified triangular trimer model, which captures electron behavior at one-third filling in twisted bilayer graphene. Though simple, the model shows rich physics, including fractional excitations and fracton-lik...

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Main Authors: Kevin Zhang, Dan Mao, Eun-Ah Kim, Roderich Moessner
Format: Article
Language:English
Published: Nature Portfolio 2025-06-01
Series:Communications Materials
Online Access:https://doi.org/10.1038/s43246-025-00849-5
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author Kevin Zhang
Dan Mao
Eun-Ah Kim
Roderich Moessner
author_facet Kevin Zhang
Dan Mao
Eun-Ah Kim
Roderich Moessner
author_sort Kevin Zhang
collection DOAJ
description Abstract Recent experiments on twisted van der Waals materials, inspired our study of a simplified triangular trimer model, which captures electron behavior at one-third filling in twisted bilayer graphene. Though simple, the model shows rich physics, including fractional excitations and fracton-like particles with restricted motion. Using Monte Carlo simulations and effective field theory, we uncover two notable phases: 1. A polar fluid phase with directional order. 2. A critical trimer liquid phase, where excitations carry fractional charge and display power-law correlations. These fractionalized excitations are bionic—they carry pairs of emergent gauge charges, revealed by algebraic correlations with two distinct exponents. Our field theory supports the numerical findings and critical exponents. The triangular trimer model emerges as a key platform to study fractionalization and fractons, where bionic monomers can evolve into fractons in nearby phases. This motivates experimental work in twisted van der Waals systems and materials with intermediate-range interactions.
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spelling doaj-art-d3934e0d01a945df80f85576e669340b2025-08-20T03:14:46ZengNature PortfolioCommunications Materials2662-44432025-06-01611810.1038/s43246-025-00849-5Bionic fractionalization in the trimer model of twisted bilayer grapheneKevin Zhang0Dan Mao1Eun-Ah Kim2Roderich Moessner3Department of Physics, Cornell UniversityDepartment of Physics, Cornell UniversityDepartment of Physics, Cornell UniversityMax Planck Institute for the Physics of Complex SystemsAbstract Recent experiments on twisted van der Waals materials, inspired our study of a simplified triangular trimer model, which captures electron behavior at one-third filling in twisted bilayer graphene. Though simple, the model shows rich physics, including fractional excitations and fracton-like particles with restricted motion. Using Monte Carlo simulations and effective field theory, we uncover two notable phases: 1. A polar fluid phase with directional order. 2. A critical trimer liquid phase, where excitations carry fractional charge and display power-law correlations. These fractionalized excitations are bionic—they carry pairs of emergent gauge charges, revealed by algebraic correlations with two distinct exponents. Our field theory supports the numerical findings and critical exponents. The triangular trimer model emerges as a key platform to study fractionalization and fractons, where bionic monomers can evolve into fractons in nearby phases. This motivates experimental work in twisted van der Waals systems and materials with intermediate-range interactions.https://doi.org/10.1038/s43246-025-00849-5
spellingShingle Kevin Zhang
Dan Mao
Eun-Ah Kim
Roderich Moessner
Bionic fractionalization in the trimer model of twisted bilayer graphene
Communications Materials
title Bionic fractionalization in the trimer model of twisted bilayer graphene
title_full Bionic fractionalization in the trimer model of twisted bilayer graphene
title_fullStr Bionic fractionalization in the trimer model of twisted bilayer graphene
title_full_unstemmed Bionic fractionalization in the trimer model of twisted bilayer graphene
title_short Bionic fractionalization in the trimer model of twisted bilayer graphene
title_sort bionic fractionalization in the trimer model of twisted bilayer graphene
url https://doi.org/10.1038/s43246-025-00849-5
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AT danmao bionicfractionalizationinthetrimermodeloftwistedbilayergraphene
AT eunahkim bionicfractionalizationinthetrimermodeloftwistedbilayergraphene
AT roderichmoessner bionicfractionalizationinthetrimermodeloftwistedbilayergraphene