Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 4: Topological insulators and spin-dependent transport phenomena

MA 4.9: Vortrag

Montag, 1. April 2019, 11:45–12:00, H52

Symmetry aspects of spin-filtering in molecular junctions: hybridization and quantum interference effects — •Dongzhe Li1 and Alexander Smogunov21Department of Physics, University of Konstanz, D-78457 Konstanz, Germany — 2Service de Physique de l’Etat Condensé, CEA, CNRS, Université Paris-Saclay, CEA Saclay, Gif-sur-Yvette F-91191, France

Control and manipulation of electric current and especially its degree of spin polarization across single molecules is currently of great interest in the field of molecular spintronics. Using state-of-the-art ab initio transport calculations, we explore one of possible strategies based on the modification of nanojunction symmetry which can be realized, for example, by a mechanical strain. Such modification can activate new molecular orbitals which were inactive before due to their orbital mismatch with electrode’s conduction states. This can result in several important consequences such as: i) a significant suppression of the majority spin conductance was found in low symmetry configurations due to quantum interference effects seen as Fano-like features in electron transmission functions and ii) strongly enhanced conductance of minority spin due to increased molecule-metal hybridization when the symmetry is lowered. We illustrate the idea on two basic molecular junctions: Ni/Benzene/Ni (perpendicular vs tilted orientations) and Ni/Si chain/Ni (zigzag vs linear chains). We believe that our results may offer new potential route for creating molecular devices with a large on/off spin polarization via quantum interference effects.

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