Eur. Phys. J. B 60, 51-60 (2007)
https://doi.org/10.1140/epjb/e2007-00325-x

Fano resonances in stubbed quantum waveguides with impurities

¹ Dipartimento di Fisica “G. Galilei”, Università di Padova, Via F. Marzolo 8, 35131 Padova, Italy
² Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Via F. Marzolo 8, 35131 Padova, Italy

Corresponding author: ^a giorgio.cattapan@pd.infn.it

Received: 26 April 2007
Revised: 5 September 2007
Published online: 29 November 2007

Abstract

We consider T–shaped, two–dimensional quantum waveguides containing attractive or repulsive impurities with a smooth, realistic shape, and study how the resonance behavior of the total conductance depends upon the strength of the defect potential and the geometry of the device. The resonance parameters are determined locating the relevant S–matrix poles in the Riemann energy surface. The total scattering operator is obtained from the S–matrices of the various constituent segments of the device through the –product composition rule. This allows for a numerically stable evaluation of the scattering matrix and of the resonance parameters.