Contact effects in spin transport along double-helical molecules



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Ai-Min, Guo and Díaz García, Elena and Gaul, C. and Gutierrez, R. and Domínguez-Adame Acosta, Francisco and Cuniberti, G. and Sun, Qing-feng (2014) Contact effects in spin transport along double-helical molecules. Physical review B, 89 (20). ISSN 1098-0121

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We report on spin transport along double-helical molecular systems by considering various contact configurations and asymmetries between the two helical strands in the regime of completely coherent charge transport. Our results reveal that no spin polarization appears in two-terminal molecular devices when coupled to one-dimensional electrodes. The same holds in the case of finite-width electrodes if there is a bottleneck of one single site in the system electrode-molecule-electrode. Then, additional dephasing is necessary to induce spin-filtering effects. In contrast, nonzero spin polarization is found in molecular devices with multiple terminals or with two finite-width electrodes, each of them connected to more than one site of the molecule. The magnitude of spin polarization can be enhanced by increasing the asymmetry between the two strands. We point out that the spin-filtering effects could emerge in double-helical molecular devices at low temperature without dephasing by a proper choice of the electrode number and the connection between the molecule and the electrodes.

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© 2014 American Physical Society.
This work was supported by the DAAD (54367888), by NBRP of China (2012CB921303), by MINECO (Grants No. PRI-AIBDE-2011-0.927 and No. MAT 2010-17180), by NSFChina under Grant No. 11274364, and by PDSF-China under Grant No. 2013M540153. We acknowledge support from the German Excellence Initiative: Cluster of Excellence EXC 1056 “Center for Advancing Electronics Dresden” (cfAED). A.M.G. and E.D. contributed equally to this work.

Uncontrolled Keywords:Single dna-molecules; Electron transmission; Hole transfer; Conductivity; Selectivity; Conductance; Phase
Subjects:Sciences > Physics > Materials
ID Code:29638
Deposited On:20 Apr 2015 08:51
Last Modified:20 Apr 2015 14:38

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