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arXiv · 2207.01638

Topological Mott Insulator at Quarter Filling in the Interacting Haldane Model

Peizhi Mai·Benjamin E. Feldman·Philip W. Phillips
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Abstract

While the recent advances in topology have led to a classification scheme for electronic bands described by the standard theory of metals, a similar scheme has not emerged for strongly correlated systems such as Mott insulators in which a partially filled band carries no current. By including interactions in the topologically non-trivial Haldane model, we show that a quarter-filled state emerges with a non-zero Chern number provided the interactions are sufficiently large. We first motivate this result on physical grounds and then by two methods: analytically by solving exactly a model in which interactions are local in momentum space and then numerically through the corresponding Hubbard model. All methods yield the same result: For sufficiently large interaction strengths, the quarter-filled Haldane model is a ferromagnetic topological Mott insulator with a Chern number of unity. Possible experimental realizations in cold-atom and solid state systems are discussed.

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Peizhi Mai, Benjamin E. Feldman, Philip W. Phillips. 2022-07-04. Topological Mott Insulator at Quarter Filling in the Interacting Haldane Model. https://doi.org/10.1103/physrevresearch.5.013162

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