Kondo effect in a semiconductor quantum dot coupled to ferromagnetic electrodes

Abstract

Using a laterally fabricated quantum-dot (QD) spin-valve device, we experimentally study the Kondo effect in the electron transport through a semiconductor QD with an odd number of electrons (N). In a parallel magnetic configuration of the ferromagnetic electrodes, the Kondo resonance at N=3 splits clearly without external magnetic fields. With applying magnetic fields (B), the splitting is gradually reduced, and then the Kondo effect is almost restored at B=1.2T. This means that, in the Kondo regime, an inverse effective magnetic field of B∼1.2T can be applied to the QD in the parallel magnetic configuration of the ferromagnetic electrodes.