论文标题
无序石墨烯量子点的原子崩溃
Atomic Collapse in Disordered Graphene Quantum Dots
论文作者
论文摘要
在本文中，我们从数值上研究了限制在无序石墨烯量子点中的dirac fermions的库仑杂质问题。在存在随机分布的晶格缺陷和空间电势波动的情况下，主要通过在扩展的平均景点Hubbard模型中的状态计算的局部密度研究了临界耦合常数对原子塌陷的响应。我们发现两种疾病都会导致临界阈值的扩增。结果，据报道，临界耦合常数增加了34％。这种数值结果可以解释为什么库仑杂质在实验中仍然是亚临界值，即使它们在理论上是超临界的。我们的结果还指出，在诸如Ar $^{+} $ ion等缺陷样品中可以观察到原子崩溃的可能性，他$^{+} $ ion被照射和氢化石墨烯。
In this paper, we numerically study a Coulomb impurity problem for interacting Dirac fermions restricted in disordered graphene quantum dots. In the presence of randomly distributed lattice defects and spatial potential fluctuations, the response of the critical coupling constant for atomic collapse is mainly investigated by local density of states calculations within the extended mean-field Hubbard model. We find that both types of disorder cause an amplification of the critical threshold. As a result, up to thirty-four percent increase in the critical coupling constant is reported. This numerical result may explain why the Coulomb impurities remain subcritical in experiments, even if they are supercritical in theory. Our results also point to the possibility that atomic collapse can be observed in defect-rich samples such as Ar$^{+}$ ion bombarded, He$^{+}$ ion irradiated, and hydrogenated graphene.
