PARAMETRIZATION OF SCATTERERS IN THE LANDAUER-BUTTIKER TRANSPORT-THEORY

Electronic dc transport along a finite chain of scatterers that allow for elastic as well as inelastic processes is described within the Landauer-Buttiker approach. The transport channels in the chain are locally coupled via (current-conserving) side channels to electron reservoirs or heat baths that provide the phase randomization. Different choices for the parameters describing the inelastic coupling as well as the elastic (transmission and reflection) coefficients are compared. The scattering matrix of the chain is calculated with a recursive method. We show that the most general individual scatterer can be characterized by five parameters only, and that it r-an be represented by a subset of unitary 4 X 4 matrices. In order to demonstrate the influence of the inelastic-scattering parameters, we investigate the fluctuations of the chemical potential measured by a probe in front of an elastic scatterer. We find that-even in the noninvasive limit-the oscillations of the chemical potential with the distance between the two scatterers depend strongly on the choice of the scattering matrix representing the probe. Our results are discussed in the context of previous investigations.