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基于石墨烯电极的Co-Salophene分子器件的自旋输运 被引量:2
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作者 陈伟 陈润峰 +5 位作者 李永涛 俞之舟 徐宁 卞宝安 李兴鳌 汪联辉 《物理学报》 SCIE EI CAS CSCD 北大核心 2017年第19期295-303,共9页
采用基于非平衡格林函数结合第一性原理的密度泛函理论的计算方法,研究了基于锯齿型石墨纳米带电极的Co-Salophene分子器件的自旋极化输运性质.计算结果表明,当左右电极为平行自旋结构时,自旋向上的电流明显大于自旋向下的电流,自旋向... 采用基于非平衡格林函数结合第一性原理的密度泛函理论的计算方法,研究了基于锯齿型石墨纳米带电极的Co-Salophene分子器件的自旋极化输运性质.计算结果表明,当左右电极为平行自旋结构时,自旋向上的电流明显大于自旋向下的电流,自旋向下的电流在[-1V,1V]偏压下接近零,分子器件表现出优异的自旋过滤效应.与此同时,在自旋向上电流中发现负微分电阻效应.当左右电极为反平行自旋结构时,器件表现出双自旋过滤和双自旋分子整流效应.除此之外,整个分子器件还表现出较高的巨磁阻效应.通过分析器件的自旋极化透射谱、局域态密度、电极的能带结构和分子自洽投影哈密顿量,详细解释该分子器件表现出众多特性的内在机理.研究结果对设计多功能分子器件具有重要的借鉴意义. 展开更多
关键词 自旋输运 分子器件 石墨烯纳米带
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Valley-polarized pumping current in zigzag graphene nanoribbons with different spatial symmetries
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作者 Zhizhou Yu Fuming Xu 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第12期110-114,共5页
We numerically investigate the valley-polarized current in symmetric and asymmetric zigzag graphene nanoribbons(ZGNRs) by the adiabatic pump, and the effect of spatial symmetry is considered by introducing different p... We numerically investigate the valley-polarized current in symmetric and asymmetric zigzag graphene nanoribbons(ZGNRs) by the adiabatic pump, and the effect of spatial symmetry is considered by introducing different pumping regions. It is found that pumping potentials with the symmetry Vp(x,y) = Vp(-x,y)can generate the largest valleypolarized current. The valley-polarized currents I13~L with the pumping potential symmetry Vp(x,y) =Vp(x,-y,) and I14~L with Vp(x,y) = Vp(-x,-y) of symmetric ZGNRs are much smaller than those of asymmetric ZGNRs. We also find I13~L and I14~L of symmetric ZGNRs decrease and increase with the increasing pumping amplitude, respectively. Moreover, the dephasing effect from the electron-phonon coupling within the Buttiker dephasing scheme is introduced. The valley-polarized current of the symmetric ZGNRs with Vp(x,y)= Vp(x,-y) increases with the increase of the dephasing strength while that with Vp(x,y) = Vp(-x,-y) decreases as the dephasing strength increases. 展开更多
关键词 valley polarization charge pump graphene quantum transport
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