Antiferromagnetically ordered Mott insulator and d+id superconductivity in twisted bilayer graphene: a quantum Monte Carlo study  

作　　者：Tongyun Huang Lufeng Zhang Tianxing Ma 

机构地区：[1]Department of Physics, Beijing Normal University

出　　处：《Science Bulletin》2019年第5期310-314,共5页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(11374034 and 11334012);Beijing Natural Science Foundation(1192011);support of HSCC of Beijing Normal University;the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund

摘　　要：Using exact quantum Monte Carlo method, we examine the recent novel electronic states seen in magicangle graphene superlattices. From the Hubbard model on a double-layer honeycomb lattice with a rotation angle θ=1:08°, 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 increases 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 shares the similar superconducting mechanism of high temperature superconductors, which is a new and ideal platform for further investigating the strongly correlated phenomena.Using exact quantum Monte Carlo method, we examine the recent novel electronic states seen in magicangle graphene superlattices. From the Hubbard model on a double-layer honeycomb lattice with a rotation angle θ=1:08°, 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 increases 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 shares the similar superconducting mechanism of high temperature superconductors, which is a new and ideal platform for further investigating the strongly correlated phenomena.

关 键 词：TWISTED BILAYER graphene MOTT insulator SUPERCONDUCTIVITY QUANTUM Monte Carlo 

分 类 号：N[自然科学总论]