Abstract: Recent experiments have discovered that pentalayer-graphene subject to a moire superlattice spontaneously breaks time-reversal, resulting in a quantized anomalous Hall effect at zero magnetic field. At fractional filling, the material exhibits a zero-field fractional quantum Hall effect. In contrast to other moire-materials, the origin of Chern bands in this material is not so clear. I will present a theoretical picture in which Chern bands arise from an “anomalous Hall crystal” stabilized primarily by interactions. So far this picture is supported mainly by mean-field calculations, so I’ll conclude with some open questions about how the Hall crystal could be verified.
Speaker Bio: Michael Zaletel is an Associate Professor of Physics and the Allison and Thomas Schneider Chair at UC Berkley.
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2024-04-18T10:00:002024-04-18T11:00:00Anomalous Hall Crystals in Graphene: interaction-driven Chern bands at zero magnetic fieldEvent Information:
Abstract: Recent experiments have discovered that pentalayer-graphene subject to a moire superlattice spontaneously breaks time-reversal, resulting in a quantized anomalous Hall effect at zero magnetic field. At fractional filling, the material exhibits a zero-field fractional quantum Hall effect. In contrast to other moire-materials, the origin of Chern bands in this material is not so clear. I will present a theoretical picture in which Chern bands arise from an “anomalous Hall crystal” stabilized primarily by interactions. So far this picture is supported mainly by mean-field calculations, so I’ll conclude with some open questions about how the Hall crystal could be verified.
Speaker Bio: Michael Zaletel is an Associate Professor of Physics and theAllison and Thomas Schneider Chair at UC Berkley.Event Location:
BRIM 311