Band structure of twisted bilayer graphene: Emergent symmetries, commensurate approximants, and Wannier obstructions
Band structure of twisted bilayer graphene: Emergent symmetries, commensurate approximants, and Wannier obstructions
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DOI：
10.1103/physrevb.98.085435
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发表时间：
2018-06
影响因子：
3.7
通讯作者：
Liujun Zou;Liujun Zou;H. Po;A. Vishwanath;T. Senthil
中科院分区：
文献类型：
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作者：
Liujun Zou;Liujun Zou;H. Po;A. Vishwanath;T. Senthil
受魔角双层石墨烯相关绝缘行为和超导性这一令人兴奋的发现的启发，作者在此讨论了该系统能带结构的显着特征。一个显着的特征是在魔角周围出现孤立的、几乎平坦的带。作者讨论了该系统的新兴对称性的重要性，并澄清了有关扭曲双层石墨烯的相应结构的一些潜在混淆。此外，他们还讨论了能带拓扑结构，该拓扑结构阻碍了构造近平坦能带的局域化 Wannier 函数，并给出了克服这些困难的方向。
Motivated by the exciting discovery of correlated insulating behavior and superconductivity in magic-angle bilayer graphene, the authors discuss here the salient features of the band structure of this system. A remarkable feature is the appearance of isolated, nearly flat bands around the magic angles. The authors discuss the importance of emergent symmetries of this system and clarify some potential confusion regarding commensurate structures of twisted bilayer graphene. Furthermore, they discuss the band topology, which leads to obstructions to constructing well-localized Wannier functions of the nearly flat bands, and give directions towards overcoming the difficulties.