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arXiv · 1804.00302

Inter-valley spiral order in the Mott insulating state of a heterostructure of trilayer graphene-boron nitride

Guo-Yi Zhu·Tao Xiang·Guang-Ming Zhang
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Abstract

Recent experiment has shown that the ABC-stacked trilayer graphene-boron nitride Moire super-lattice at half-filling is a Mott insulator. Based on symmetry analysis and effective band structure calculation, we propose a valley-contrasting chiral tight-binding model with local Coulomb interaction to describe this Moire super-lattice system. By matching the positions of van Hove points in the low-energy effective bands, the valley-contrasting staggered flux per triangle is determined around $\pi /2$. When the valence band is half-filled, the Fermi surfaces are found to be perfectly nested between the two valleys. Such an effect can induce an inter-valley spiral order with a gap in the charge excitations, indicating that the Mott insulating behavior observed in the trilayer graphene-boron nitride Moire super-lattice results predominantly from the inter-valley scattering.

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Guo-Yi Zhu, Tao Xiang, Guang-Ming Zhang. 2018-04-01. Inter-valley spiral order in the Mott insulating state of a heterostructure of trilayer graphene-boron nitride. https://doi.org/10.1016/j.scib.2018.06.022

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