2008/07/24 by V. Vyurkov, V. Ryzhii
Chemistry · Materials Science · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Graphene research and applications #Quantum and electron transport phenomena #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1134/s0021364008170074
4 pages, 3 figures, to be published in JETP Lett
arxiv created 2008/07/24 · openalex publication_date 2008/11/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The effect of the Coulomb scattering on graphene conductivity in field-effect transistor structures is discussed. Interparticle scattering (electron-electron, hole-hole, and electron-hole) and scattering on charged defects are taken into account in a wide range of gate voltages. It is shown that an intrinsic conductivity of graphene (purely ambipolar system, where both electron and hole densities exactly coincide) is defined by a strong electron-hole scattering. It has a universal value independent of the temperature. We give an explicit derivation based on the scaling theory. When there is even a small discrepancy in the electron and hole densities caused by the applied gate voltage, the conductivity is determined by both a strong electron-hole scattering and a weak external scattering: on the defects or phonons. We suggest that the density of the charged defects (occupancy of defects) depends on the Fermi energy to explain the sublinear dependence of conductivity on a fairly high gate voltage observed in the experiments. We also eliminate the contradictions between the experimental data obtained in the deposited and suspended graphene structures regarding the graphene conductivity.