Modeling A.C. electronic transport through a two-dimensional quantum point contact

Abstract

We present new results on the a.c. transport of electrons moving through a two-dimensional (2D) semicondutor quantum point contact (QPC). We concentrate our attention on the characteristic properties of the high frequency admittance (ω ≈ 0 – 50GHz), and on the oscillations of the admittance in the vicinity of the separatrix (when a channel opens or closes), in presence of the relaxation effects. The experimental verification of these oscillations in the admittance would be a strong confirmation of our semi-classical approach to a.c. transport through a QPC, in the separatrix region.