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  • Letter
  • Open Access

Spontaneous fractional Chern insulators in transition metal dichalcogenide moiré superlattices

Heqiu Li1, Umesh Kumar2, Kai Sun1, and Shi-Zeng Lin3

  • 1Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
  • 2Theoretical Division, T-4, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
  • 3Theoretical Division, T-4 and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

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Phys. Rev. Research 3, L032070 – Published 22 September, 2021

DOI: https://doi.org/10.1103/PhysRevResearch.3.L032070

Abstract

The Moiré superlattice realized in two-dimensional heterostructures offers an exciting platform to access strongly correlated electronic states. In this work, we study transition metal dichalcogenides (TMD) Moiré superlattices with time-reversal symmetry and nontrivial spin/valley-Chern numbers. Utilizing realistic material parameters and the method of exact diagonalization, we find that at a certain twisting angle and fractional filling, gapped fractional topological states, i.e., fractional Chern insulators, are naturally stabilized by simply introducing the Coulomb repulsion. In contrast to fractional quantum Hall systems, where the time-reversal symmetry has to be broken explicitly, these fractional states break the time-reversal symmetry spontaneously. We show that the Chern number contrasting in the opposite valleys imposes a strong constraint on the nature of fractional Chern insulator and the associated low-energy excitations.

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Phys. Rev. Research 3, L032070– Published 22 September, 2021
  • Received 4 January 2021
  • Revised 15 June 2021
  • Accepted 24 August 2021
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