Hwang E H, Adam S, Sarma S Das
Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA.
Phys Rev Lett. 2007 May 4;98(18):186806. doi: 10.1103/PhysRevLett.98.186806. Epub 2007 May 3.
Carrier transport in gated 2D graphene monolayers is considered in the presence of scattering by random charged impurity centers with density n(i). Excellent quantitative agreement is obtained (for carrier density n>10(12) cm(-2)) with existing experimental data. The conductivity scales linearly with n/n(i) in the theory. We explain the experimentally observed asymmetry between electron and hole conductivities, and the high-density saturation of conductivity for the highest mobility samples. We argue that the experimentally observed saturation of conductivity at low density arises from the charged impurity induced inhomogeneity in the graphene carrier density which becomes severe for n less, similarn(i) approximately 10(12) cm(-2).
在存在密度为n(i)的随机带电杂质中心散射的情况下，考虑了门控二维石墨烯单层中的载流子输运。（对于载流子密度n>10(12) cm(-2)），与现有实验数据取得了出色的定量一致性。在该理论中，电导率与n/n(i)呈线性比例关系。我们解释了实验观察到的电子和空穴电导率之间的不对称性，以及最高迁移率样品电导率的高密度饱和现象。我们认为，实验观察到的低密度下电导率的饱和是由带电杂质引起的石墨烯载流子密度不均匀性导致的，当n小于、近似于n(i)约10(12) cm(-2)时，这种不均匀性变得严重。
