Quasiparticle tunneling between quasi-one-dimensional charge density waves

Abstract

The tunneling current (ac and dc) between two charge density wave (CDW) phase domains in the standard geometry of a point contact is calculated. Temperature Green's functions for pure CDW and the transfer Hamiltonian of Artemenko and Volkov are used to compute the current analytically. In the dc response anomalous terms — not described by the phase difference between the two CDW — vanish by an average over the relative phase of the direct and backscattering transfer matrix elements. For small ac amplitude excitations the linear ac response function is obtained. Extension to the more realistic pseudo-gap structure is achieved by using Sadovskii's method of resumming all diagrams for the one particle Green's function — including the crossing diagrams — which carry a momentumK=2kF. The method results in averages over effective gap values which are carried out analytically. The corresponding results for Re σ(ω) are displayed. They show absorption also inside the gap region.