Absence of thermal smearing for the transmission phase through a quantum dot

¹ Yale University, Department of Applied Physics - New Haven, CT 06520, USA
² Max-Planck-Institut für Kernphysik - 69029 Heidelberg, Germany

Received: 2 December 1996
Accepted: 27 February 1997

Abstract

We derive the phase θ of the Aharonov-Bohm oscillations of a multi-terminal electron ring with a quantum dot in one of its arms. We show i) that θ varies smoothly by π at each transmission peak of the system. We also find ii) that θ drops sharply by π between the peaks if consecutive peaks have similar resonance parameters. The characteristic energy scale for ii) is of the order of the intrinsic resonance width . This fact can be employed to measure in a novel way.