TEMPORAL CORRELATION OF ELECTRONS - SUPPRESSION OF SHOT-NOISE IN A BALLISTIC QUANTUM POINT-CONTACT

Wideband shot noise, associated with de current flow through a quantum point contact (QPC), is measured in the microwave frequency range of 8-18 GHz. As the number of conducting channels in the QPC changes the noise power oscillates. Consistent with existing theories, the noise p eaks depend linearly on the de current. Surprisingly, however, in the pinch off region, where QPC is expected to behave as a classical injec tor, we find strong noise suppression, possibly mediated by the Coulom b interaction.