[Cohérence de phase entre bicouche et fermions composites]
L’effet Hall quantique fractionnaire (FQHE) réalisé dans les systèmes électroniques bidimensionnels s’explique par l’émergence de fermions composites (CF) à partir d’électrons ordinaires. Il est possible d’écrire des fonctions d’onde explicites expliquant de nombreux, voire tous les états de l’effet Hall quantique fractionnaire. Dans les systèmes formés de bicouches, il existe un régime de remplissage entier du niveau de Landau le plus bas qui présente une brisure spontanée de la phase relative U(1) entre les deux couches. Cela peut être considéré comme une cohérence de phase entre les couches (ILC) en termes d’électrons. Des expériences récentes dans des échantillons à double couche de graphène ont révélé l’apparition de nombreux états FQHE propres au cas bicouche. Nous discutons des extensions de l’idée de CF dans cette situation ainsi que de l’existence possible d’ILC de CFs.
The fractional quantum Hall effect (FQHE) realized in two-dimensional electron systems is explained by the emergent composite fermions (CF) out of ordinary electrons. It is possible to write down explicit wavefunctions explaining many if not all FQHE states. In bilayer systems there is a regime at integer filling of the lowest Landau level that displays a spontaneous breakdown of the U(1) relative phase between the two layers. This can be seen as interlayer phase coherence (ILC) in terms of electrons. Recent experiments in double layer samples of graphene have revealed the appearance of many FQHE states unique to the bilayer case. We discuss extensions of the CF idea in this situation as well as the possible existence of ILC of CFs.
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Mots-clés : Effet Hall quantique, Fermions composites, Coherence entre couches, Bicouche de graphene
Thierry Jolicoeur 1
CC-BY 4.0
@article{CRPHYS_2025__26_G1_113_0,
author = {Thierry Jolicoeur},
title = {Interlayer phase coherence and composite fermions},
journal = {Comptes Rendus. Physique},
pages = {113--124},
publisher = {Acad\'emie des sciences, Paris},
volume = {26},
year = {2025},
doi = {10.5802/crphys.232},
language = {en},
}
Thierry Jolicoeur. Interlayer phase coherence and composite fermions. Comptes Rendus. Physique, Volume 26 (2025), pp. 113-124. doi : 10.5802/crphys.232. https://comptes-rendus.academie-sciences.fr/physique/articles/10.5802/crphys.232/
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