Path integral description of a semiclassical Su-Schrieffer-Heeger model

The electron motion along a chain is described by a continuum version of the Su-Schrieffer-Heeger Hamiltonian, in which phonon fields and electronic coordinates are mapped onto the time scale. The path-integral formalism allows us to derive the nonlocal source action for the particle interacting with the oscillators bath. The method can be applied for any value of the e-ph coupling. The path-integral dependence on the model parameters has been analyzed by computing the partition function and some thermodynamical properties from T=1 K up to room temperature. A peculiar upturn in the low-temperature heat capacity over temperature ratio (pointing to a glassy like behavior) has been ascribed to the time-dependent electronic hopping along the chain.