Spin-Resolved Transport Properties of a Pyridine-Linked Single Molecule Embedded between Zigzag-Edged Graphene Nanoribbon Electrodes

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• 作者：Xiaobo Li ; Liemao Cao ; Hui-Li Li ; Haiqing Wan ; Guanghui Zhou
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：February 11, 2016
• 年：2016
• 卷：120
• 期：5
• 页码：3010-3018
• 全文大小：721K
• ISSN：1932-7455

文摘

We study the spin-dependent electron transport through a junction consisting of a single pyridine-linked (PDL) molecule sandwiched between two zigzag-edged graphene nanoribbon (ZGNR) electrodes modulated by an external magnetic field, where 4,4′-bipyridine, 4,4′-vinylenedipyridine, and 4,4′-ethylenedipyridine molecules are considered, respectively. By using ab initio calculations based on the density functional theory combined with nonequilibrium Green’s function formalism, it is shown that the spin-charge transport can be modulated by performing different magnetic configuration in the ZGNR electrodes. Specifically, we demonstrate that the proposed PDL molecular junctions exhibit several interesting effects, including (dual) spin-filtering, rectifying, negative differential resistance (NDR), and magnetoresistance. For the junction consisting of a 4,4′-bipyridine molecule with proper magnetic configuration in the two ZGNRs, it is interesting to note that a perfect spin polarization with filtering efficiency up to 100% can be found, the maximum value of rectification ratio can reach up to 10⁴, and the peak to valley ratio of NDR reach up to 328, respectively. Furthermore, the magnetoresistance ratio for this junction can also go up to 10⁶%. Besides, the physical mechanisms for those phenomenons are revealed. The mechanisms are revealed and analyzed by the connection of these effects to the evolution of the frontier molecular orbital, the spin-resolved transmission spectrum associated with the local density of states around the Fermi level at zero bias, and the molecular projected self-consistent Hamiltonian.