Coulomb oscillations of the current through spin-nondegenerate p states of InAs quantum dots

The electron transport is studied in split-gate structures fabricated on the basis of a modulation-doped heterostructure that contains a single quantum well and self-assembled InAs quantum dots near the 2D electron gas regions. The current passing through the channel with a denumerable set of InAs quantum dots is found to exhibit Coulomb oscillations as a function of the gate voltage. The oscillations are associated with the excited p states of InAs quantum dots, which are characterized by opposite spins and caused by lifting of the spin degeneracy of the p state due to the Coulomb interaction. The Coulomb oscillations of the current are observed up to a temperature of similar to 20 K. The Coulomb energy is found to be Delta E-c = 12.5 meV, which agrees well with the theoretical estimates for the p states of quantum dots in the structures under study. (C) 2005 Pleiades Publishing, Inc.