Asymmetric quantum dots in an applied electric field: discontinuous electron density

Abstract

We consider non-interacting electrons in asymmetric quantum dots with either hard wall boundary conditions (rectangular quantum dots) or anharmonic confinement (elliptic quantum dots). In both cases, due to finite size effects, a homogeneous electric field applied along the long axis is shown to induce abrupt changes in the electron density, parallel and perpendicular to the field direction. Making use of this property, we propose a pure electrical mechanism to control the magnitude of the effective exchange interaction between two weakly-coupled quantum dots. This kind of system has been proposed recently as possible realization of quantum gates for quantum computation.