Ground-State Cooling of a Carbon Nanomechanical Resonator by Spin-Polarized Current

Year: 2014

Authors: Stadler P., Belzig W., Rastelli G.

Autors Affiliation: Univ Konstanz, Fachbereich Phys, D-78457 Constance, Germany; Univ Konstanz, D-78457 Constance, Germany

Abstract: We study the nonequilibrium steady state of a mechanical resonator in the quantum regime realized by a suspended carbon nanotube quantum dot in contact with two ferromagnets. Because of the spin-orbit interaction and/or an external magnetic field gradient, the spin on the dot couples directly to the flexural eigenmodes. Accordingly, the nanomechanical motion induces inelastic spin flips of the tunneling electrons. A spin-polarized current at finite bias voltage causes either heating or active cooling of the mechanical modes. We show that maximal cooling is achieved at resonant transport when the energy splitting between two dot levels of opposite spin equals the vibrational frequency. Even for weak electron-resonator coupling and moderate polarizations we can achieve ground-state cooling with a temperature of the leads, for instance, of T = 10 omega.

Journal/Review: PHYSICAL REVIEW LETTERS

Volume: 113 (4)      Pages from: 047201  to:

More Information: We thank O. Arcizet, V. Bouchiat, G. Burkard, A. K. Huttel, E. Scheer, E. Weig, and W. Wernsdorfer for useful and stimulating discussions. This research was kindly supported by the EU FP7 Marie Curie Zukunftskolleg Incoming Fellowship Programme, University of Konstanz (Grant No. 291784) and the DFG through SFB 767 and BE 3803/5.
KeyWords: quantum dots, quantum transport, quantum electromechanical systems, spin transport
DOI: 10.1103/PhysRevLett.113.047201

ImpactFactor: 7.512
Citations: 47
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