Optical conductivity of the two-dimensional Kondo lattice in spin–polaron approach

Abstract

In the framework of the two dimensional Kondo lattice model the optical conductivity spectrum σ( ω) is investigated. The calculations are based on the realistic energy spectrum of spin–polaron excitations to fit photoemission experiments in cuprates. The memory function approach is used for deriving σ( ω). Obtained optical transport damping, plasma frequency and conductivity demonstrate qualitative agreement with experimental data. It is pointed out the crucial importance of nested Fermi surface scattering by vector Q =(π,π) due to strong carrier coupling to a resonance structure of spin excitations with momenta close to Q .