Abstract
We report measurements of the Kondo effect in a double quantum dot, where the orbital states act as pseudospin states whose degeneracy contributes to Kondo screening. Standard transport spectroscopy as a function of the bias voltage on both dots shows a zero-bias peak in conductance, analogous to that observed for spin Kondo in single dots. Breaking the orbital degeneracy splits the Kondo resonance in the tunneling density of states above and below the Fermi energy of the leads, with the resonances having different pseudospin character. Using pseudospin-resolved spectroscopy, we demonstrate the pseudospin character by observing a Kondo peak at only one sign of the bias voltage. We show that even when the pseudospin states have very different tunnel rates to the leads, a Kondo temperature can be consistently defined for the double quantum dot system.
- Received 6 July 2012
DOI:https://doi.org/10.1103/PhysRevLett.110.046604
© 2013 American Physical Society
Synopsis
Probing Kondo Physics with a Light Touch
Published 24 January 2013
A new scheme exploiting the orbital rather than the spin degree of freedom allows for studying the Kondo effect without disturbing it.
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