Tuning Fano-type resonances in coupled quantum point contacts by   applying asymmetric voltages
  We study the ballistic magnetotransport in a double quantum point contact (QPC) device consisting of a quasi-one-dimensional quantum wire with an embedded island-like impurity - etched nano-hole as in a recently published experiment [J. C. Chen, Y. Lin, K.-T. Lin, T. Ueda and S. Komiyama, Appl. Phys. Lett. 94, 012105 (2009)]. We reproduce the zero field quantized conductance, the interference phenomenon induced by the coupled QPCs, as well as the Ramsauer-like resonances observed in the experiments. At finite magnetic fields Fano-type resonances arises in the conductance due to the formation of localized states at the impurity periphery and to an inter-edge state resonant coupling effect. It is predicted that the Fano-type resonances can be controlled by an asymmetric confinement of the QPCs. 
Rub\'en C. Villarreal, Francisco Mireles, Ernesto E. Marinero and   Bruce A. Gurney
cond-mat.mes-hall