Perfect spin filtering and large spin thermoelectric effects in organic transition-metal molecular junctions.
We present ab initio studies of spin-polarized transport properties and thermospin effects in cyclopentadienyl-iron molecular junctions. It is found that the spin-up transmission coefficient at the Fermi level shows an odd-even oscillating behaviour, while the spin-down transmission coefficient has an exponential decay with the molecule length. The spin polarization at the Fermi level rapidly tends toward a saturation value close to 100% with the molecule length. This is ascribed to the existence of different orbital states for different spin components at the Fermi level. In addition, we find that the spin-up Seebeck coefficient oscillates between positive and negative values, while the spin-down Seebeck coefficient always has a positive value and monotonically increases with the molecule length. Therefore in some cases, the spin Seebeck coefficient is even larger than the corresponding charge Seebeck effect. Finally, we also provide a possibility of utilizing cyclopentadienyl-iron molecular junctions to achieve the pure spin current without an accompanying charge current at about room temperature.
College of Physics and Engineering and Jiangsu Laboratory of Advanced Functional materials, Changshu Institute of Technology, Changshu 215500, China. ysliu@cslg.edu.cn fengjinfu@cslg.edu.cn.
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Yang
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Liu
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Zhang
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Zhou
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Wang
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Chi
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Feng