Geometrical effects in transport through quantum wires with side-coupled quantum dots

Ómar Valsson
Science Institute, University of Iceland,
Dunhaga 3
IS-107 Reykjavik, Iceland

Email: omarv@raunvis.hi.is

Abstract
The coherent electronic transport in quantum wires with embedded nanostructures is investigated within a theoretical framework consisting of the Landauer-Buttiker formalism and a quasi-1D Lippmann-Schwinger scattering formalism. The conductance of a clean ballistic quantum wire exhibits step like quantization. However, the embedded nanostructures are expected to introduced deviations to the quantization. The focus of this work is on quantum wire with side-coupled quantum dots. These quantum wire systems show in general a rich conductance structure caused mainly by quasi-bound states in the quantum dots. A quantum wire with two side-coupled quantum dots shows indication of a peculiar state, so called bound state in the continuum. A simple model of a closed quantum dot with a similar geometry as the side-coupled quantum dots is introduced. This model is used to characterize the quasi-bound states in the open side-coupled quantum dots.