The kondo effect in the unitary limit
We observe a strong Kondo effect in a semiconductor quantum dot when a small magnetic field is applied. The Coulomb blockade for electron tunneling is overcome completely by the Kondo effect, and the conductance reaches the unitary limit value. We compare the experimental Kondo temperature with the theoretical predictions for the spin- 12 Anderson impurity model. Excellent agreement is found throughout the Kondo regime. Phase coherence is preserved when a Kondo quantum dot is included in one of the arms of an Aharonov-Bohm ring structure, and the phase behavior differs from previous results on a non-Kondo dot.
van der Wiel WG
Department of Applied Physics, Delft Institute for Microelectronics and Submicrontechnology, and ERATO Mesoscopic Correlation Project, Delft University of Technology, Post Office Box 5046, 2600 GA Delft, Netherlands. NTT Basic Research Laboratories,
De Franceschi S
Fujisawa
T
Elzerman
JM
Tarucha
S
Kouwenhoven
LP