论文标题
扭曲双层石墨烯的手性近似:精确的谷体内反式对称性,淋巴结结构以及对较高魔法角度的影响
Chiral Approximation to Twisted Bilayer Graphene: Exact Intra-Valley Inversion Symmetry, Nodal Structure and Implications for Higher Magic Angles
论文作者
论文摘要
本文对“魔术”扭曲角度的扭曲双层石墨烯的手性模型中的平面波形进行了数学和数值分析。我们表明,手性模型具有精确的valley倒置对称性。将平面波函数写为最低的Landau级量子厅状态和一个旋转器的产物,我们表明旋转器的组件是此处介绍的反转对称操作相关的反量子霍尔波函数。然后,我们从数字上表明,随着一个人从最低的魔法角度移动到更高的魔法角度,波函数的旋转组件会显示出越来越多的零角度,类似于随着Landau水平指数的增加,量子霍尔波函数的变化。波函数的零的特征是手性,在摩尔单位单元中心附近的相同手性聚类的零,而相反的手性零被推到单位单元的边界。更高的魔法角度的增强相绕组表明循环电流增加。讨论了对扫描隧道光谱,轨道磁化和相互作用效应的物理意义。
This paper presents a mathematical and numerical analysis of the flatband wavefunctions occurring in the chiral model of twisted bilayer graphene at the "magic" twist angles. We show that the chiral model possesses an exact intra-valley inversion symmetry. Writing the flatband wavefunction as a product of a lowest Landau level quantum Hall state and a spinor, we show that the components of the spinor are anti-quantum Hall wavefunctions related by the inversion symmetry operation introduced here. We then show numerically that as one moves from the lowest to higher magic angles, the spinor components of the wavefunction exhibit an increasing number of zeros, resembling the changes in the quantum Hall wavefunction as the Landau level index is increased. The wavefunction zeros are characterized by a chirality, with zeros of the same chirality clustering near the center of the moire unit cell, while opposite chirality zeros are pushed to the boundaries of the unit cell. The enhanced phase winding at higher magic angles suggests an increased circulating current. Physical implications for scanning tunneling spectroscopy, orbital magnetization and interaction effects are discussed.