一维铁磁/有机系统的基态与自旋分布研究

Ground state properties and spin density of ferromagnetic metal/conjugated polymer system

文中用一维紧束缚模型描述铁磁金属,用一维非简并的Su Schrieffer Heeger(SSH)模型描述共轭聚合物,研究了在一维铁磁/共轭聚合物系统和一维CMR材料/聚合物系统中的电子转移和自旋转移。发现在聚合物部分没有自旋的双极化子比有自旋的极化子具有较低的能量而容易产生。然而在铁磁CMR材料/聚合物系统中极化子的产生能低于聚合物中极化子的产生能,增加了有机物中自旋极化输运的可能性。

In this paper the charge and spin transfer in ferromagnetic metal/conjugated polymer system were investigated. We used an one-dimensional nondegenerate Su-Schrieffer-Heeger (SSH) Hamiltonian to describe the conjugated polymer and one-dimensional tight-binding model to describe the ferromagnetic metal. It was found that bipolarons were the lowest energy charge state in the bulk polymer. As a result electrons (or holes) transferred into the bulk of the polymer form spinless bipolarons. However, the creation energy of polaron in the ferromagnetic metal was lower than that in ferromagnetic CMR/conjugated polymer system, which made it possible the spin polarization transfer in conjugated polymers.