Center for Nanophysics and Advanced Materials, University of Maryland, College Park, 20742, USA.
Phys Rev Lett. 2011 Nov 11;107(20):206601. doi: 10.1103/PhysRevLett.107.206601. Epub 2011 Nov 7.
We study electron transport properties of graphene in the presence of correlated charged impurities via adsorption and thermal annealing of potassium atoms. For the same density of charged scattering centers, the sample mobility sensitively depends on temperature which sets the correlation length between the scatterers. The data are well-understood by a recent theory that allows us to quantitatively extract the temperature dependence of the correlation length. Impurity correlations also offer a self-consistent explanation to the puzzling sublinear carrier-density dependence of conductivity commonly observed in monolayer graphene samples on substrates.
我们通过钾原子的吸附和热退火来研究相关带电杂质存在下石墨烯的电子输运性质。对于相同密度的带电散射中心，样品迁移率对温度非常敏感，而温度则决定了散射体之间的相关长度。最近的一项理论很好地解释了这些数据，该理论使我们能够定量提取相关长度随温度的变化。杂质相关性也为在衬底上的单层石墨烯样品中普遍观察到的电导率与载流子密度呈次线性关系这一令人困惑的现象提供了自洽的解释。
