Phys. Rev. B 72, 121302(R) (2005) [4 pages]Gate-controlled spin splitting in quantum dots with ferromagnetic leads in the Kondo regime
The effect of a gate voltage (Vg) on the spin splitting of an electronic level in a quantum dot (QD) attached to ferromagnetic leads is studied in the Kondo regime using a generalized numerical renormalization group technique. We find that the Vg dependence of the QD level spin splitting strongly depends on the shape of the density of states (DOS). For one class of DOS shapes there is nearly no Vg dependence; for another, Vg can be used to control the magnitude and sign of the spin splitting, which can be interpreted as a local exchange magnetic field. We find that the spin splitting acquires a new type of logarithmic divergence. We give an analytical explanation for our numerical results and explain how they arise due to spin-dependent charge fluctuations. © 2005 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.72.121302
DOI:
10.1103/PhysRevB.72.121302
PACS:
73.23.Hk, 72.15.Qm, 72.25.−b, 75.20.Hr
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