The impact of gas molecule adsorption on the orbital magnetic susceptibility of graphene

We investigate the effect of gas molecule adsorption on the density of states and orbital magnetic susceptibility of graphene. We use Green's function approach and coherent potential approximation within a tight-binding description. The results show that the gas adsorption causes a finite density of states at zero energy in contrast to the pure case where the density of states vanishes. We also find that the temperature dependent of orbital magnetic susceptibility is sensitive to the gas molecule concentration as it changes into two temperature regions. The susceptibility increases as temperature increases in the low temperature region, and after a crossover, decreases as temperature increases at high temperatures.