The Two-Commponent Model and 2d Metal-Insulator Transition

Fermi liquid theory for the 2d MIT is extended to include the soft correlation gap (CG) in the density-of-states N(E) from carrier interactions [N(E)alpha(E-E_F)t] producing a minimum in N(E) at E_F. The results are consistent with the scaling form g=g_cexp(xT_o/T) in a limited T-regime, but not as Trightarrow0 ruling out the perfect conductor scenario. The two-component model of itinerant plus localized electrons n_i+n_loc=n=n_c(1+x) for n > n_c is an essential feature and allows a full explanation of the T-dependence of the metallic resistivity ratio rho_i(T)/rho_i(0) [rho_i= 1/(sigma-sigma_c)] including the maximum at T_max. The results explain the Hanein et al. data1 for p-type GaAs and show p_i(T)/p_i(0)=1+T/T_phi in a restricted T-range where T_phi=xT_c [T_c=E_c/k, E_c=mobility edge] as x=p/p_c-1 goes to 0. The correction to E_F from the soft CG [of width |Delta_c] yields a constant ratio E_F/Delta_c as Xgoes to 0. The origin of the nonuniversal g_c [rho_c at x=0] and implications for the beta function beta(g)=ln(g/g_c) and single particle scaling will be discussed. 1. Y. Hanein et al., PRL80, 1288 (1998);Phys.Rev.B58, R13338 (1998).