Unusually large spin polarization and magnetoresistance in a FeMg8-FeMg8 superatomic dimer.
J Chem Phys
; 139(6): 064306, 2013 Aug 14.
Article
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| MEDLINE
| ID: mdl-23947854
ABSTRACT
Electronic transport across a FeMg8 magnetic superatom and its dimer has been investigated using a density functional theory combined with Keldysh nonequilibrium Green's-function formalism. For a single cluster, our studies for the cluster supported in various orientations on a Au(100) surface show that the transport is sensitive to the contact geometry. Investigations covering the cases where the axes of Mg square antiprism are 45°, perpendicular, and parallel to the transport direction, show that the equilibrium conductance, transferred charge, and current polarizations can all change significantly with orientation. Our studies on the transport across a magnetic superatom dimer FeMg8-FeMg8 focus on the effect of electrode contact distance and the support. The calculated I-V curves show negative differential resistance behavior at larger electrode-cluster contact distances. Further, the equilibrium conductance in ferromagnetic state shows an unusually high spin polarization that is about 81.48% for specific contact distance, and a large magnetoresistance ratio exceeding 500% is also found. The results show that the superatom assemblies can provide unusual transport characteristics, and that the spin polarization and magnetoresistance can be controlled via the contact geometry.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
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En
Revista:
J Chem Phys
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos