Mesoscopic phase behavior in a quantum dot around crossover between single-level and multilevel transport regimes
Takada, S. and Yamamoto, M. and Bäuerle, C. and Ludwig, A. and Wieck, A.D. and Tarucha, S.
PHYSICAL REVIEW B
Volume: 95 Pages:
The transmission phase across a quantum dot (QD) is expected to show mesoscopic behavior, where the appearance of a phase lapse between Coulomb peaks (CPs) as a function of the gate voltage depends on the orbital parity relation between the corresponding CPs. On the other hand, such mesoscopic behavior has been observed only in a limited QD configuration (a few-electron and single-level transport regime) and universal phase lapses by π between consecutive CPs have been reported for all the other configurations. Here, we report on the measurement of a transmission phase across a QD around the crossover between single-level and multilevel transport regimes employing an original two-path quantum interferometer. We find mesoscopic behavior for the studied QD. Our results show that the universal phase lapse, a longstanding puzzle of the phase shift, is absent for a standard QD, where several tens of successive well-separated CPs are observed. ©2017 American Physical Society.