The generic fixed point model for pseudo-spin-1/2 quantum dots in nonequilibrium: Spin-valve systems with compensating spin polarizations

摘要

We study a pseudo-spin-1/2 quantum dot in the cotunneling regime close to theparticle-hole symmetric point. For a generic tunneling matrix we find a genericfixed point with interesting nonequilibrium properties, characterized byeffective reservoirs with compensating spin orientation vectors weighted by thepolarizations and the tunneling rates. At large bias voltage we study themagnetic field dependence of the dot magnetization and the current. The fixedpoint can be clearly identified by analyzing the magnetization of the dot. Wecharacterize in detail the universal properties for the case of two reservoirs.