Interaction correction of conductivity near a ferromagnetic quantum critical point

Abstract

We calculate the temperature dependence of conductivity due to interaction correction for a disordered itinerant electron system close to a ferromagnetic quantum critical point, which occurs due to a spin-density wave instability. In the quantum critical regime, the crossover between diffusive and ballistic transport occurs at a temperature T* = 1/[{tau}{gamma}(e{sub F}{tau}){sup 2}], where {gamma} is the parameter associated with the Landau damping of the spin fluctuations, {tau} is the impurity scattering time, and E{sub F} is the Fermi energy. For a generic choice of parameters, T* is a few orders of magnitude smaller than the usual crossover scale 1/{tau}. In the ballistic quantum critical regime, the conductivity has a T{sup (d-1)/3} temperature dependence where d is the dimensionality of the system. In the diffusive quantum critical regime, we get T{sup 1/4} dependence in three dimensions and In{sup 2} T dependence in two dimensions. Away from the quantum critical regime, we recover the standard results for a good metal.