Conduction through a Quantum Dot near a Singlet-Triplet Transition

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 $T$ are obtained. At $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$, the conductance reaches the unitary limit $\ensuremath{\sim}{4e}^{2}/h$ 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.

Locations

• Physical Review Letters - View
• arXiv (Cornell University) - View - PDF
• PubMed - View
• DataCite API - View