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HL: Fachverband Halbleiterphysik

HL 8: Transport: Quantum dots, wires, point contacts 1 (TT, jointly with HL, O)

HL 8.7: Vortrag

Montag, 11. März 2013, 11:15–11:30, H20

Spin dynamics in nanoparticles near Stoner instability — •Philipp Stegmann¹, Björn Sothmann², Jürgen König¹, and Yuval Gefen³ — ¹Theoretische Physik, Universität Duisburg-Essen and CENIDE, 47048 Duisburg, Germany — ²Départment de Physique Théorique, Université de Genève, CH-1211 Genève 4, Switzerland — ³Dept. of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel

We analyse the spin dynamics of a nanoparticle close to the Stoner instability. The nanoparticle is weakly tunnel coupled to two ferromagnetic leads. By mapping to an effective Fokker-Planck description we identify two different types of dynamic behaviour (diffusion vs. drift), which are revealed by characteristic relaxation times and a Fano factor that oscillates as a function of an applied bias voltage. Finally, we propose biasing schemes to generate states with magnetic quadrupole moments that dominate over a negligible dipole moment.