凝聚态物理
堆积
电子能带结构
超晶格
费米能量
格子(音乐)
六边形晶格
双层石墨烯
带隙
物理
石墨烯
近自由电子模型
双层
电子结构
材料科学
电子
一维晶格中的粒子
量子力学
互易晶格
化学
核磁共振
反铁磁性
衍射
声学
生物化学
膜
作者
Nguyen N. T. Nam,Mikito Koshino
出处
期刊:Physical review
日期:2017-08-28
卷期号:96 (7)
被引量:411
标识
DOI:10.1103/physrevb.96.075311
摘要
We theoretically study the lattice relaxation in the twisted bilayer graphene (TBG) and its effect on the electronic band structure. We develop an effective continuum theory to describe the lattice relaxation in general TBGs and obtain the optimized structure to minimize the total energy. At small rotation angles $< 2^{\circ}$, in particular, we find that the relaxed lattice drastically reduces the area of AA-stacking region, and form a triangular domain structure with alternating AB and BA stacking regions. We then investigate the effect of the domain formation on the electronic band structure. The most notable change from the non-relaxed model is that an energy gap up to 20meV opens at the superlattice subband edges on the electron and hole sides. We also find that the lattice relaxation significantly enhances the Fermi velocity, which was strongly suppressed in the non-relaxed model.
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