封装进过渡金属原子的单壁碳纳米管：密度泛函理论研究

摘要

The transport properties of a single wall carbon tube with transition metal atoms embedded in it are studied by using the first principles method based on the density functional theory and the nonequilibrium Green’s function. Different transition metal atoms filled in the carbon tube are investigated, and the respective charge and spin transport properties are studied. The conductance of the nanotube is found to be distinctive for different metal elements encapsulated, and quantized reductions of conductance can be seen by a quantum unit (2e2/h). In particular, nanotubes with two iron atoms encapsulated in display different I-V curves when the spins of the two iron atoms are in parallel and antiparallel states respectively. These results can be explained by spin-dependent scattering and charge transfer. The encapsulation may tailor the doping and add magnetic behavior to the carbon nanotubes, which would provide a new and promising approach to detect nanoscale magnetic activity.%运用基于第一性原理的密度泛函理论(DFT)的非平衡格林函数(NEGF)方法对过渡金属原子嵌入后的单壁碳纳米管(SWCNT)的电子输运性质进行了研究。构建并优化不同过渡金属原子填充进不同类型碳纳米管的模型，研究其对应的电荷和自旋传输性质。发现所有体系都在费米面附近出现自旋相关的电导下降峰，数值为一个量子电导(2e2/h)。碳管内封装两个铁原子的体系，磁性状态的改变导致不同的电输运行为，这一性质提供了新的有前景的方法来检测原子尺度上的磁特性。