Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 46: Transport: Nanomechanics (jointly with MM)
TT 46.4: Vortrag
Dienstag, 17. März 2015, 14:45–15:00, A 053
Spin-vibration interaction in a nanomechanical spin-valve — •Pascal Stadler1, Wolfgang Belzig1, and Gianluca Rastelli1,2 — 1Fachbereich Physik, Universität Konstanz, 78457 Konstanz, Germany — 2Zukunftskolleg, Fachbereich Physik, Universität Konstanz, 78457, Konstanz, Germany
We study spin-dependent transport in a suspended carbon nanotube quantum dot in contact with two ferromagnetic leads and with the dot’s spin interacting with the flexural modes [1,2]. The spin-vibration interaction arises from the spin-orbit coupling or a magnetic field gradient. We use a nonequilibrium Green’s functions technique to evaluate the phonon occupation and the transport properties. The interaction between the spin and the vibration leads to a mechanical damping and, for an applied bias-voltage, to a steady nonequilibrium occupation of the harmonic oscillator. Depending on the magnetic configuration and the bias voltage polarity, a single vibrational mode can be strongly cooled, heated or can approach a regime of a mechanical instability. Owing to the sensitivity of the electron transport to the spin orientation, we find signatures of the nanomechanical motion in the current-voltage characteristic.
[1] P. Stadler, W. Belzig, and G. Rastelli,
Phys. Rev. Lett. 113, 047201 (2014).
[2] P. Stadler, W. Belzig, and G. Rastelli, arXiv:1408:6357.