Extraction of the short-range defect potential parameters from available experimental data on the graphene resistance

Abstract

We consider a problem of obtaining information about the scattering potentials of the monolayer graphene sample using available experimental data on its resistance. For this purpose, we study theoretically the dependence of graphene resistance on Fermi energy having in mind to compare it with experimental data where super-high mobility electrons in suspended graphene samples without chemical doping were investigated. As far as practical absence of the doping impurities in this case makes the Coulomb scattering negligible, we consider models of the short-range scattering potentials. The model of short-range potential is assumed to be supported by the close vicinity of the ring or the circumference of a circle. The diameter of circles is supposed to be of the order of the crystal lattice spacing. The empty core of the model potential guarantees the suppression of nonphysical shortwave modes. Two models are investigated: the delta function on the circumference of a circle (delta shell) and the annual well. An advantage of the former is simplicity, while a virtue of the latter is regularity. We consider scattering of electrons by these potentials and obtain exact explicit formulae for the scattering data. We here discuss application of these formulae for calculation of observables. Namely, we analyze the contribution of this scattering into the graphene resistance and plot the resistivity as a function of the Fermi energy according to our theoretical formulae. The obtained results are consistent with experiment, where the resistance was measured as a function of the Fermi momentum on the suspended annealed graphene. This fact gives a possibility to find parameters of the modeled potential on the basis of the available experimental data on resistance of the suspended graphene sample with the gate voltage controlled Fermi level position. It is clear to be very important for applications.