Density of states and transport properties of a diluted honeycomb lattice

Abstract

The effect of site dilution in the transport properties of a single graphite plane at half-filling is discussed in terms of Dirac fermions. The density of states is computed using the coherent potential approximation (CPA). It is found that the effect of disorder is the induction of a finite density of states at zero energy. We study the electric conductivity as function of temperature T and frequency ω for different site dilutions n i , within the CPA. For the optical conductivity σ ( ω ) at low temperature, a quasi-scaling behavior of the form σ ( ω / n i ) is found, as a consequence of the universal limit of the conductivity σ ( 0 ) at zero temperature.