Department of Physics and the Center of Theoretical and Computational Physics, The University of Hong Kong, Hong Kong, China.
Nanoscale. 2017 Aug 31;9(34):12684-12689. doi: 10.1039/c7nr03532b.
The spin-filter transport and magnetoresistance effects are of particular interest in the field of molecular spintronics. In this work, based on first-principles quantum transport calculations, we report on the spin-dependent transport properties of a molecular junction made of two manganese phthalocyanine (MnPc) molecules linked by single-walled carbon nanotubes. Owing to the half-metallicity of MnPc around the Fermi energy, a perfect spin-filter effect and a giant magnetoresistance effect are observed in the molecular junction. The current-voltage characteristics show nearly ohmic behavior for the junction in an anti-parallel magnetic configuration, while a very low-bias negative differential resistance effect is observed for the junction in a parallel magnetic configuration. The results are well understood from the analysis of molecular frontier orbitals, scattering states and transmission spectra. Our results provide some fundamental understanding of spin-dependent transport in molecular junctions that are useful for the design of future spintronic devices.
自旋过滤输运和磁电阻效应在分子自旋电子学领域具有特别的意义。在这项工作中，我们基于第一性原理量子输运计算，研究了由两个通过单壁碳纳米管连接的锰酞菁（MnPc）分子组成的分子结的自旋相关输运性质。由于 MnPc 在费米能级附近的半金属性质，在分子结中观察到了完美的自旋过滤效应和巨大的磁电阻效应。电流-电压特性表明，在反平行磁构型下，结具有近乎欧姆的行为，而在平行磁构型下，结则表现出非常低偏压的负微分电阻效应。通过对分子前沿轨道、散射态和透射谱的分析，可以很好地理解这些结果。我们的结果为分子结中自旋相关输运提供了一些基本的理解，这对于设计未来的自旋电子器件是有用的。
