论文标题
石墨烯中的分子塌陷：sublattice对称效应
Molecular collapse in graphene: sublattice symmetry effect
论文作者
论文摘要
由于石墨烯具有较大的“有效”结构常数，因此可以在石墨烯中观察到原子崩溃，这使得这种现象的杂质电荷可能低至$ z_c \ sim 1-2 $。在这里，我们研究了Sublattice对称性对两个空间分离电荷可调空位中分子塌陷的影响，这些空间位于相同（A-A类型）或不同（A-B类型）的Sublattices上。我们发现损坏的sublattice对称性：（1）不影响主要键合和反键的分子塌陷峰的位置，（2），但会改变卫星峰的位置，因为它们是当地倾斜对称性的破坏的结果，并且（3）在空缺峰值方面，可以实现空缺的峰值，而b型的峰值则是跨度的，而be则跨度跨越了空中峰值的峰值。 A-A类型。随着电荷，能量和分离距离的增加，额外的塌陷特征与主分子塌陷峰合并。我们表明，塌陷状态的空置位点周围的空间分布使我们能够将分子与沮丧的崩溃区分开。
Atomic collapse can be observed in graphene because of its large "effective" fine structure constant, which enables this phenomenon to occur for an impurity charge as low as $Z_c\sim 1-2$. Here, we investigate the effect of the sublattice symmetry on molecular collapse in two spatially separated charge tunable vacancies, that are located on the same (A-A type) or different (A-B type) sublattices. We find that the broken sublattice symmetry: (1) does not affect the location of the main bonding and anti-bonding molecular collapse peaks, (2) but shifts the position of the satellite peaks, because they are a consequence of the breaking of the local sublattice symmetry, and (3) there are vacancy characteristic collapse peaks that only occur for A-B type vacancies, which can be employed to distinguish them experimentally from the A-A type. As the charge, energy, and separation distance increase, the additional collapse features merge with the main molecular collapse peaks. We show that the spatial distribution around the vacancy site of the collapse states allows us to differentiate the molecular from the frustrated collapse.
