Anomalous Kondo-effect in Quantum Dot at non-zero bias

Abstract

We present measurements on the Kondo-effect in a small quantum dot connected strongly to one lead and weakly to the other. The conductance of the dot reveals an offset of the Kondo resonance at zero magnetic field. While the resonance persists in the negative bias regime, it is suppressed in the opposite direction. This demonstrates the pinning of the Kondo resonance to the Fermi levels of the left and right lead. As an outlook we exploit the spin blockade effect to gain information about the spin state of the quantum dot in the Kondo regime.