2006/10/31 by Alexandre Reily Rocha, Stefano Sanvito, Rocha, Alexandre Reily +1
Chemistry · Engineering · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.cond-mat/0610866
openalex publication_date 2006/10/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate theoretically the effects of surface states over the magnetoresistance of Ni-based organic spin-valves. In particular we perform \it ab initio electronic transport calculations for a benzene-thiolate molecule chemically attached to a Ni [001] surface and contacted either by Te to another Ni [001] surface, or terminated by a thiol group and probed by a Ni STM tip. In the case of S- and Te-bonded molecules we find a large asymmetry in the spin-currents as a function of the bias, although the I-V is rather symmetric. This leads to a smooth although not monotonic dependence of the magnetoresistance over the bias. In contrast, in the case of a STM-type geometry we demonstrate that the spin-current and the magnetoresistance can be drastically changed with bias. This is the result of a resonance between a spin-polarized surface state of the substrate and the d-shell band-edge of the tip.