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TT: Fachverband Tiefe Temperaturen

TT 6: TR: Nanoelectronics II: Spintronics and Magnetotransport

TT 6.11: Vortrag

Montag, 22. März 2010, 16:45–17:00, H19

Interference spin-blockade in symmetric nanojunctions — •Andrea Donarini, Georg Begemann, and Milena Grifoni — Institut für Theoretische Physik, Universität Regensburg

Nanojunctions with a high degree of spatial symmtry, like molecular junctions, but also specially designed multiple quantum dot structures, have a degenerate many body spectrum. The degeneracy is in fact protected by symmetry. The interference between the degenerate states causes a novel current blocking mechanism that allows, in presence of polarized leads, the all electric control of the spin and orbital degree of freedom on the junction. We present here a general formalism to give necessary and sufficient conditions for interference blockade. As an example we analyze a triple dot single electron transistor (SET) [1]. In particular, we show how to prepare the system in each of the three spin states of the excited 2-electrons triplet state without application of any external magnetic field.

[1] Nano Letters, 9, 2897 (2009).