Baber scattering and resistivity of a two-dimensional two-band model

Abstract

We investigate the Baber scattering problem in two dimensions, for the resistivity of a two-band model. The circular Fermi surface is two sheeted, light s electrons scatter against heavy d electrons characterized by a Fermi temperature T_F(d). For T≫ T_F(d) a saturation of the temperature dependence is expected, whereas for T≪T_F(d) a Fermi-liquid behavior is recovered. The details of the crossover are studied by analytical and numerical methods. At low temperatures we show the existence of a T²ln(T^*/T) behavior for the case of commensurate density, k₃=kd, and calculate the T* analytically. In the generic case of noncommensurate density, k^s≠k_d, there is no logarithmic correction. We study the region of validity of the low-temperature expansion by comparing with exact numerical evaluations and find, in many cases, an extremely small domain of validity for the low-temperature expansion. We discuss the possible application of these ideas to high-T_c systems.