论文标题
扭曲的双层石墨烯中的新兴对称和山谷Chern绝缘子
Emergent Symmetry and Valley Chern Insulator in Twisted Double-Bilayer Graphene
论文作者
论文摘要
理论计算表明，在横向电场下，扭曲的双重双层石墨烯（TDBG）在电荷中立时形成了Chern Number 2。使用热力学和热激活测量结果，我们报告了TDBG HofStadter频谱中电荷中性间隙的普遍截止的实验观察，每个单位电池都以1/2磁通量为单位磁通量，这与Valley Chern Number Chern 2 GAP的理论预测一致。我们对实验数据的理论分析表明，相互作用的能量大于1°的TDBG中的平坦带宽并不会改变新兴的山谷对称性或单粒子带拓扑。
Theoretical calculations show that twisted double bilayer graphene (TDBG) under a transverse electric field develops a valley Chern number 2 at charge neutrality. Using thermodynamic and thermal activation measurements we report the experimental observation of a universal closing of the charge neutrality gap in the Hofstadter spectrum of TDBG at 1/2 magnetic flux per unit cell, in agreement with theoretical predictions for a valley Chern number 2 gap. Our theoretical analysis of the experimental data shows that the interaction energy, while larger than the flat-band bandwidth in TDBG near 1°does not alter the emergent valley symmetry or the single-particle band topology.
