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arXiv · 2107.07149

Effective continuum model of twisted bilayer GeSe and origin of emerging one-dimensional mode

Manato Fujimoto·Toshikaze Kariyado
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Abstract

The electric structure of twisted bilayer GeSe, which shows a rectangular moiré pattern, is analyzed using a $\bm{k}\cdot\bm{p}$ type effective continuum model. The effective model is constructed on the basis of the the local approximation method, where the local lattice structure of a twisted bilayer system is approximated by its untwisted bilayer with parallel displacement, and the required parameters are fixed with the help of the first-principles method. By inspecting the twist angle dependence of the physical properties, we reveal a relation between the effective potential under moiré pattern and the alignment of the Ge atoms, and also the resultant one-dimensional flat band, where the band is flattened stronger in a specific direction than the perpendicular direction. Due to the relatively large effective mass of the original monolayers, the flat band with its band width as small as a few meV appear in a relatively large angle. This gives us an opportunity to explore the dimensional crossover in the twisted bilayer platform.

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Manato Fujimoto, Toshikaze Kariyado. 2021-07-15. Effective continuum model of twisted bilayer GeSe and origin of emerging one-dimensional mode. https://doi.org/10.1103/physrevb.104.125427

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