扰动对有机磁体器件自旋极化输运特性的影响  

Effect of disturbance on spin polarized transport through an organic ferromagnetic device

作　　者：王辉[1] 胡贵超[1] 任俊峰[1] 

机构地区：[1]山东师范大学物理与电子科学学院,济南250014

出　　处：《物理学报》2011年第12期468-477,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10904084;10904083);山东省优秀中青年科学家科研奖励基金(批准号:2009BS01009);山东省高等学校科技奖励计划(批准号:J09LA03)资助的课题~~

摘　　要：基于紧束缚模型和格林函数方法,研究了有机磁体晶格扰动和侧基自旋取向扰动对金属/有机磁体/金属三明治结构有机自旋器件自旋极化输运特性的影响.计算结果表明:晶格扰动的存在降低了器件的起始偏压,减小了导通电流,并使得电流-电压曲线的量子台阶效应不再显著,扰动不太强时电流仍呈现较高的自旋极化率;而侧基自旋取向扰动减小了体系的自旋劈裂,增加了器件的起始偏压,低偏压下随着扰动的增强器件电流及其自旋极化率明显降低.进一步模拟了温度对器件自旋极化输运的影响.Based on the tight-binding model and the Green＇s function method,the effects of atomic disorder of lattice configuration and the orientation disorder of side radical spins on the spin polarized transport through a metal/organic-ferromagnet/metal structure are investigated.The results show that the atomic disorder reduces the threshold voltage of the device and suppresses the conducting current.The staircase structure of the current-voltage curve for a molecular device is eliminated when the disorder is enhanced.The current keeps a high spin polarization if the atomic disorder is not strong.The orientation disorder of side radical spins reduces the spin splitting of molecular energy levels,which increases the threshold voltage of the device.The current and its spin polarization are reduced apparently at a low bias when the strength of disorder is enhanced.We further simulate the effect of temperature on the spin polarized transport through the device by taking into account two kinds of disorders.

关 键 词：有机自旋电子学 有机磁体 自旋极化输运 自旋过滤 

分 类 号：O469[理学—凝聚态物理]