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arXiv · 1804.06096

Antiferromagnetically ordered Mott insulator and $d+id$ superconductivity in twisted bilayer graphene: A quantum Monte carlo study

Tongyun Huang·Lufeng Zhang·Tianxing Ma
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Abstract

Using exact quantum Monte Carlo method, we examine the recent novel electronic states seen in magic-angle graphene superlattices. From the Hubbard model on a double-layer honeycomb lattice with a rotation angle $θ=1.08^{\circ}$, we reveal that an antiferromagnetically ordered Mott insulator emerges beyond a critical $U_c$ at half filling, and with a small doping, the pairing with $d+id$ symmetry dominates over other pairings at low temperature. The effective $d+id$ pairing interaction strongly increase as the on-site Coulomb interaction increases, indicating that the superconductivity is driven by electron-electron correlation. Our non-biased numerical results demonstrate that the twisted bilayer graphene share the similar superconducting mechanism of high temperature superconductors, which is a new and idea platform for further investigating the strongly correlated phenomena.

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Tongyun Huang, Lufeng Zhang, Tianxing Ma. 2018-07-02. Antiferromagnetically ordered Mott insulator and $d+id$ superconductivity in twisted bilayer graphene: A quantum Monte carlo study. https://doi.org/10.1016/j.scib.2019.01.026

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