Microscopic theory of the pseudogap and Peierls transition in quasi-one-dimensional materials

The problem of deriving from microscopic theory a Ginzburg-Landau free-energy functional to describe the Peierls or charge-density-wave transition in quasi-one-dimensional materials is considered. Particular attention is given to how the thermal lattice motion affects the electronic states. Near the transition temperature the thermal lattice motion produces a pseudogap in the density of states at the Fermi level. Perturbation theory diverges and the traditional quasiparticle or Fermi-liquid picture breaks down. The pseudogap causes a significant modification of the coefficients in the Ginzburg-Landau functional from their values in the rigid lattice approximation, which neglects the effect of the thermal lattice motion.