Electron ground state in concentric GaAs‐(Ga,Al)As single and double quantum rings

Abstract

AbstractWe study the effect of geometric confinement on the electron states in a concentric double quantum ring. We calculate the energy of the electron ground state for both symmetric and asymmetric double quantum rings as a function of the radius of the inner and outer rings, the barrier height and as a function of an applied magnetic field. We found that the probability amplitude for the electron state is approximately the same in the inner and outer wells of the structure when the width of the wells is the same, but there is a noticeable change in the probability amplitude in the well regions when the width of the inner well is slightly different from the outer one (asymmetric rings). As a result the carrier energy changes considerably from one situation to the other. On the other hand the barrier width between the inner and outer ring plays an important role in the definition of the energy of the electron ground state up to the extent that for certain values of the barrier and well widths, the energy of the ground state does not depend any more on the barrier width. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)