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 peaks depend linearly on the de current. Surprisingly, however, in the pinch off region, where QPC is expected to behave as a classical injector, we find strong noise suppression, possibly mediated by the Coulomb interaction.