TRANSMISSION THROUGH A QUANTUM-DOT IN AN AHARONOV-BOHM RING

Motivated by a recent experiment by Yacoby et al. [Phys. Rev. Lett. 74 , 4047 (1995)]. we calculate the transmission through a quantum dot wh ich is embedded in one arm of an Aharonov-Bohm (AB) ring. We allow for several channels in the AB ring. The electron-electron interaction wi thin the dot is treated in a self-consistent mean-field approximation. We show that the amplitude of the Phi(0)-periodic Aharonov-Bohm oscil lations generically vanishes close to a conductance resonance of the d ot. This leads to a sudden phase change by pi in these oscillations, i n agreement with observation.