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arXiv · 0801.4736

Single particle relaxation time versus transport scattering time in a 2D graphene layer

E. H. Hwang·S. Das Sarma
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Abstract

We theoretically calculate and compare the single-particle relaxation time ($τ_s$) defining quantum level broadening and the transport scattering time ($τ_t$) defining Drude conductivity in 2D graphene layers in the presence of screened charged impurities scattering and short-range defect scattering. We find that the ratio $τ_t/τ_s$ increases strongly with increasing $k_F z_i$ and $κ$ where $k_F$, $z_i$, and $κ$ are respectively the Fermi wave vector, the separation of the substrate charged impurities from the graphene layer, and the background lattice dielectric constant. A critical quantitative comparison of the $τ_t/τ_s$ results for graphene with the corresponding modulation-doped semiconductor structures is provided, showing significant differences between these two 2D carrier systems.

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E. H. Hwang, S. Das Sarma. 2008-01-30. Single particle relaxation time versus transport scattering time in a 2D graphene layer. https://doi.org/10.1103/physrevb.77.195412

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