Shytov A V, Katsnelson M I, Levitov L S
Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
Phys Rev Lett. 2007 Dec 7;99(23):236801. doi: 10.1103/PhysRevLett.99.236801. Epub 2007 Dec 5.
Screening of charge impurities in graphene is analyzed using the exact solution for vacuum polarization obtained from the massless Dirac-Kepler problem. For the impurity charge below a certain critical value, no density perturbation is found away from the impurity, in agreement with perturbation theory. For the supercritical charge, however, the polarization distribution is shown to have a power law profile, leading to screening of the excess charge at large distances. The Dirac-Kepler scattering states give rise to standing wave oscillations in the local density of states which are prominent in the supercritical regime.
利用从无质量狄拉克 - 开普勒问题得到的真空极化精确解，对石墨烯中电荷杂质的筛选进行了分析。对于低于某个临界值的杂质电荷，远离杂质处未发现密度扰动，这与微扰理论一致。然而，对于超临界电荷，极化分布呈现幂律分布，导致在大距离处对过量电荷进行筛选。狄拉克 - 开普勒散射态在态密度中产生驻波振荡，这种振荡在超临界区域尤为显著。
