Continuous correlated states and dual-flatness in a moiré heterostructure

Fuente: arXiv
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Hauptverfasser: Ezzi, Mohammed M. Al, Xin, Na, Shi, Yanmeng, Xu, Shuigang, Barrier, Julien, Berdyugin, Alexey, Bhattacharjee, Shubhadeep, Knothe, Angelika, Watanabe, Kenji, Taniguchi, Takashi, Falko, Vladimir, Vignale, Giovanni, Geim, Andre K., Adam, Shaffique, Novoselov, Kostya S., Kim, Minsoo
Format: Preprint
Veröffentlicht: 2026
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author Ezzi, Mohammed M. Al
Xin, Na
Shi, Yanmeng
Xu, Shuigang
Barrier, Julien
Berdyugin, Alexey
Bhattacharjee, Shubhadeep
Knothe, Angelika
Watanabe, Kenji
Taniguchi, Takashi
Falko, Vladimir
Vignale, Giovanni
Geim, Andre K.
Adam, Shaffique
Novoselov, Kostya S.
Kim, Minsoo
author_facet Ezzi, Mohammed M. Al
Xin, Na
Shi, Yanmeng
Xu, Shuigang
Barrier, Julien
Berdyugin, Alexey
Bhattacharjee, Shubhadeep
Knothe, Angelika
Watanabe, Kenji
Taniguchi, Takashi
Falko, Vladimir
Vignale, Giovanni
Geim, Andre K.
Adam, Shaffique
Novoselov, Kostya S.
Kim, Minsoo
contents Many-body effects in condensed matter yield novel quantum states when the electronic density of states is enhanced. A vivid example is flat bands, which suppress kinetic energy and let interactions dominate, when they are filled with an integer number of electrons in moire systems. Yet flat bands and commensurate fillings are not the only conditions for correlated phenomena. Situations may occur where the band structure develops locally enhanced density of states, leading to strong correlations even at non-integer fillings, although such cases often yield pseudogaps that make detection elusive. Here we demonstrate that small-angle twisted monolayer-bilayer graphene combines moire-induced global flat band and additional local band flattening. Their coexistence allows direct comparison of correlated effects. The global route stabilizes commensurate states, while the local mechanism produces nearly flat bands, lifting degeneracy and generating symmetry breaking at non-integer fillings, yet without opening a global gap. Because there is no global gapped signature, the system remains metallic, but the effect reveals itself in anomalous Hall responses, signaling time-reversal symmetry breaking and valley polarization. Our results demonstrate dual-flatness as a guiding principle, extending moire physics beyond commensurate fillings and identifying topological transport as a probe of gapless correlated metals.
format Preprint
id arxiv_https___arxiv_org_abs_2604_13958
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Continuous correlated states and dual-flatness in a moiré heterostructure
Ezzi, Mohammed M. Al
Xin, Na
Shi, Yanmeng
Xu, Shuigang
Barrier, Julien
Berdyugin, Alexey
Bhattacharjee, Shubhadeep
Knothe, Angelika
Watanabe, Kenji
Taniguchi, Takashi
Falko, Vladimir
Vignale, Giovanni
Geim, Andre K.
Adam, Shaffique
Novoselov, Kostya S.
Kim, Minsoo
Strongly Correlated Electrons
Many-body effects in condensed matter yield novel quantum states when the electronic density of states is enhanced. A vivid example is flat bands, which suppress kinetic energy and let interactions dominate, when they are filled with an integer number of electrons in moire systems. Yet flat bands and commensurate fillings are not the only conditions for correlated phenomena. Situations may occur where the band structure develops locally enhanced density of states, leading to strong correlations even at non-integer fillings, although such cases often yield pseudogaps that make detection elusive. Here we demonstrate that small-angle twisted monolayer-bilayer graphene combines moire-induced global flat band and additional local band flattening. Their coexistence allows direct comparison of correlated effects. The global route stabilizes commensurate states, while the local mechanism produces nearly flat bands, lifting degeneracy and generating symmetry breaking at non-integer fillings, yet without opening a global gap. Because there is no global gapped signature, the system remains metallic, but the effect reveals itself in anomalous Hall responses, signaling time-reversal symmetry breaking and valley polarization. Our results demonstrate dual-flatness as a guiding principle, extending moire physics beyond commensurate fillings and identifying topological transport as a probe of gapless correlated metals.
title Continuous correlated states and dual-flatness in a moiré heterostructure
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2604.13958