title: Cooling a magnetic nanoisland by spin-polarized currents.
abstract: We investigate cooling of a vibrational mode of a magnetic quantum dot by a spin-polarized tunneling charge current exploiting the magnetomechanical coupling. The spin-polarized current polarizes the magnetic nanoisland, thereby lowering its magnetic energy. At the same time, Ohmic heating increases the vibrational energy. A small magnetomechanical 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 magnetomechanical coupling. The cooling rate increases at first with the magnetomechanical coupling and then saturates.
authors.affiliation: I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Brüggemann
authors.affiliation: Theoretische Physik, Universität Duisburg-Essen and CENIDE, 47048 Duisburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Weiss
authors.affiliation: I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Nalbach
authors.affiliation: I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, 20355 Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Thorwart