Abstract
Kondo effect in the vicinity of a singlet-triplet transition in a vertical quantum dot is considered. This system is shown to map onto a special version of the two-impurity Kondo model. At any value of the control parameter, the system has a Fermi-liquid ground state. Explicit expressions for the linear conductance as a function of the control parameter and temperature are obtained. At , the conductance reaches the unitary limit at the triplet side of the transition, and decreases with the increasing distance to the transition at the singlet side. At finite temperature, the conductance exhibits a peak near the transition point.
- Received 25 May 2000
DOI:https://doi.org/10.1103/PhysRevLett.85.2993
©2000 American Physical Society