Scaling properties of mono-layer graphene away from the Dirac point

Abstract

The statistical properties of the carrier density profile of graphene in the ground state in the presence particle-particle interaction and random charged impurity in zero gate voltage has been recently obtained by Najafi \textit{et al.} (Phys. Rev E95, 032112 (2017)). The non-zero chemical potential ($μ$) in gated graphene has non-trivial effects on electron-hole puddles, since it generates mass in the Dirac action and destroys the scaling behaviors of the effective Thomas-Fermi-Dirac theory. We provide detailed analysis on the resulting spatially inhomogeneous system in the framework of the Thomas-Fermi-Dirac theory for the Gaussian (white noise) disorder potential. We show that, the chemical potential in this system as a random surface, destroys the self-similarity, and the charge field is non-Gaussian. We find that the two-body correlation functions are factorized to two terms: a pure function of the chemical potential and a pure function of the distance. The spatial dependence of these correlation functions is double-logarithmic, e.g. the two-point density correlation $D_2(r,μ)\propto μ^2\exp\left[-\left(-a_D\ln\ln r^{β_D}\right)^{α_D} \right]$ ($α_D=1.82$, $β_D=0.263$ and $a_D=0.955$). The Fourier power spectrum function behaves like $\ln(S(q))=-β_S^{-a_S}\left(\ln q \right)^{a_S}+2\ln μ$ ($a_S=3.0\pm 0.1$ and $β_S=2.08\pm 0.03$) in contrast to the ordinary Gaussian rough surfaces for which $a_S=1$ and $β_S=\frac{1}{2}(1+α)^{-1}$, ($α$ being the roughness exponent). The geometrical properties are however similar to the un-gated ($μ=0$) case, with the exponents that are reported in the text.