Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 103: Transport: Poster Session
TT 103.2: Poster
Donnerstag, 19. März 2015, 15:00–18:00, Poster B
Phonon-induced spintronics and spin cooling in quantum dots — •Stephan Weiss1, Jochen Brueggemann2, Peter Nalbach2, and Michael Thorwart2 — 1Theoretische Physik, Universität Duisburg-Essen and CENIDE, 47048 Duisburg, Germany — 2I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg
In the presence of spin dependent tunnel couplings, vibrations in quantum dots or single molecule transistors induce exchange fields which give rise to spin-accumulation and -precession for confined electrons. The effective exchange field is calculated to lowest order in the dot-lead coupling for a nonequilibrium transport setup. For realistic parameters, an effective spin-phonon coupling driven by many-body interactions, either electron-phonon or Coulomb-like, emerges [1]. We investigate the precession- and accumulation-effects of the confined spins as function of bias- and gate-voltages. In addition, we investigate the cooling of a vibrational mode of a magnetic quantum dot by a spin-polarized tunneling charge current, exploiting the interaction between the magnetization and the vibration[2]. We determine parameter regimes for the cooling of the vibration below the lead temperature.
[1] S. Weiss, J. Brueggemann, and M. Thorwart, (submitted).
[2] J. Brueggemann, S. Weiss, P. Nalbach, and M. Thorwart,
Phys. Rev. Lett. 113, 076602 (2014).