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arXiv · 2308.03143

Magic Angles and Fractional Chern Insulators in Twisted Homobilayer TMDs

Nicolás Morales-Durán·Nemin Wei·Jingtian Shi·Allan H. MacDonald
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Abstract

We explain the appearance of magic angles and fractional Chern insulators in twisted K-valley homobilayer transition metal dichalcogenides by mapping their continuum model to a Landau level problem. Our approach relies on an adiabatic approximation for the quantum mechanics of valence band holes in a layer-pseudospin field that is valid for sufficiently small twist angles and on a lowest Landau level approximation that is valid for sufficiently large twist angles. It simply explains why the quantum geometry of the lowest moir\'e miniband is nearly ideal at particular flat-band twist angles, predicts that topological flat bands occur only when the valley-dependent moir\'e potential is sufficiently strong compared to the interlayer tunneling amplitude, and provides a powerful starting point for the study of interactions

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Nicolás Morales-Durán, Nemin Wei, Jingtian Shi, Allan H. MacDonald. 2023-08-06. Magic Angles and Fractional Chern Insulators in Twisted Homobilayer TMDs. https://doi.org/10.1103/physrevlett.132.096602

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