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Exploiting the magnetomechanical interaction for cooling magnetic molecular junctions by spin-polarized currents

  • We present a scheme for cooling a vibrational mode of a magnetic molecular nanojunction by a spin-polarized charge current upon exploiting the interaction between its magnetic moment and the vibration. The spin-polarized charge current polarizes the magnetic moment of the nanoisland, thereby lowering its energy. A small but finite coupling between the vibration and the magnetic moment permits a direct exchange of energy such that vibrational energy can be transferred into the magnetic state. For positive bias voltages, this generates an effective cooling of the molecular vibrational mode. We determine parameter regimes for the cooling of the vibration to be optimal. Although the flowing charge current inevitably heats up the vibrational mode via Ohmic energy losses, we show that due to the magnetomechanical coupling, the vibrational energy (i.e, the effective phonon temperature) can be lowered below 50% of its initial value, when the two leads are polarized anti-parallel. In contrast to the cooling effect for positive bias voltages, net heating of the vibrational mode occurs for negative bias voltages. The cooling effect is enhanced for a stronger anti-parallel magnetic polarization of the leads, while the heating is stronger for a larger parallel polarization. Yet, dynamical cooling is also possible with parallel lead alignments when the two tunneling barriers are asymmetric.

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Metadaten
Verfasserangaben:Jochen Brüggemann, Stephan Weiß, Peter Nalbach, Michael Thorwart
DOI:https://doi.org/10.1088/1367-2630/18/2/023026
Titel des übergeordneten Werkes (Englisch):New Journal of Physics
Dokumentart:Wissenschaftlicher Artikel
Sprache:Englisch
Datum der Veröffentlichung (online):14.12.2016
Datum der Erstveröffentlichung:02.05.2016
Veröffentlichende Institution:Westfälische Hochschule Gelsenkirchen Bocholt Recklinghausen
Datum der Freischaltung:03.01.2017
Freies Schlagwort / Tag:demagnetization cooling; nonequilibrium quantum transport; open quantum systems
Jahrgang:18
Erste Seite:023026
Fachbereiche / Institute:Fachbereiche / Wirtschaft und Informationstechnik Bocholt
Lizenz (Deutsch):License LogoEs gilt das Urheberrechtsgesetz

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