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CDW fluctuations and the pseudogap in the single-particle conductivity of quasi-1D Peierls CDW systems: II

The current-dipole Kubo formula for the dynamical conductivity of interacting multiband electronic systems derived in Ref.~[1] is illustrated on the Peierls model for quasi-one-dimensional systems with the charge-density-wave (CDW) instability. Using the microscopic representation of the Peierls model, it is shown in which way the scattering of conduction electrons by CDW fluctuations affects the dynamical conductivity at temperatures above and well below the CDW transition temperature. The generalized Drude formula for the intraband conductivity is derived in the ordered CDW state well below the transition temperature. The natural extension of this formula to the case with the intraband memory function dependent on frequency and wave vector is also presented. It is shown that the main advantage of such a memory-function conductivity model is that it can be easily extended to study the dynamical conductivity and the electronic Raman scattering in more complicated multiband electronic systems in a way consistent with the law of conservation of energy. The incoherent interband conductivity in the CDW pseudogap state is briefly discussed as well.

Peierls CDW systems; fluctuations in the order parameter; optical conductivity

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