Abstract
We present a theoretical study based on the Anderson model of the transport properties of a Kondo impurity (atom or quantum dot) connected to ferromagnetic leads, which can sustain a nonequilibrium spin current. We analyze the case where the spin current is injected by an external source and when it is generated by the voltage bias. Due to the presence of ferromagnetic contacts, a static exchange field is produced that eventually destroys the Kondo correlations. We find that such a field can be compensated by an appropriated combination of the spin-dependent chemical potentials leading to the restoration of the Kondo resonance. In this respect, a Kondo impurity may be regarded as a very sensitive sensor for nonequilibrium spin phenomena.
Highlights
In the last decades, there has been a revived interest in Kondo physics
We have in mind situations in which the quantum dot is used as a detector of a nonequilibrium spin accumulation; we focus on the asymmetric situation in which one electrode [the left one in Fig. 1(a) or the scanning tunneling microscopy (STM) tip in Fig. 1(b)] may be partially polarized and able to sustain a spin current
Such a generic geometry can describe an artificial impurity or a genuine impurity contacted between a spin-polarized electrode
Summary
There has been a revived interest in Kondo physics. This many-body effect is produced by high-order correlated tunneling events consisting of electronic spins hopping in and out of a localized impurity, which lead to an efficient screening of the impurity spin. The impurity can be either artificial, such as a quantum dot [see Fig. 1(a)], or a genuine magnetic atom adsorbed on a surface [see Fig. 1(b)] We consider both cases in which the spin current is either driven by an external source (and constant) or driven by the same electrode (and voltage dependent). Taking into account both the static spin polarization and the spin accumulation, we show that both effects can compensate each other and the Kondo resonance can be restored. Details of the truncated equation of motion approach used are presented in Appendix
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
