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arXiv · 1908.02581

Flat Chern Band From Twisted Bilayer MnBi$_2$Te$_4$

Biao Lian·Zhaochen Liu·Yuanbo Zhang·Jing Wang
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Abstract

We construct a continuum model for the Moiré superlattice of twisted bilayer MnBi$_2$Te$_4$, and study the band structure of the bilayer in both ferromagnetic (FM) and antiferromagnetic (AFM) phases. We find the system exhibits highly tunable Chern bands with Chern number up to $3$. We show that a twist angle of $1^\circ$ turns the highest valence band into a flat band with Chern number $\pm1$ that is isolated from all other bands in both FM and AFM phases. This result provides a promising platform for realizing time-reversal breaking correlated topological phases, such as fractional Chern insulator and $p+ip$ topological superconductor. In addition, our calculation indicates that the twisted stacking facilitates the emergence of quantum anomalous Hall effect in MnBi$_2$Te$_4$.

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Biao Lian, Zhaochen Liu, Yuanbo Zhang, Jing Wang. 2023-02-16. Flat Chern Band From Twisted Bilayer MnBi$_2$Te$_4$. https://doi.org/10.1103/physrevlett.124.126402

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