Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 26: Quantum Dynamics, Decoherence and Quantum Information (jointly with DY)

TT 26.1: Vortrag

Montag, 16. März 2015, 15:00–15:15, BH-N 334

Cooling a Magnetic Nanoisland by Spin-Polarized Currents — •Peter Nalbach¹, Jochen Brüggemann¹, Stephan Weiss², and Michael Thorwart¹ — ¹I. Institut für Theoretische Physik, Universität Hamburg, Germany — ²Theoretische Physik, Universität Duisburg-Essen and CENIDE, Germany

We investigate cooling of a vibrational mode of a magnetic quantum dot by a spin-polarized tunnelling charge current exploiting the magneto-mechanical coupling. The spin-polarized current polarizes the magnetic nano-island, thereby lowering its magnetic energy. At the same time, Ohmic heating increases the vibrational energy. A small magneto-mechanical coupling then permits us to remove energy from the vibrational motion and cooling is possible. We find a reduction of the vibrational energy below 50% of its equilibrium value. The lowest vibration temperature is achieved for a weak electron-vibration coupling and a comparable magneto-mechanical coupling. The cooling rate increases at first with the magneto-mechanical coupling and then saturates.

see: Phys. Rev. Lett. 113, 076602 (2014).