Robles R, Khanna S N
Department of Physics, Virginia Commonwealth University, Richmond, Virginia 23284-2000, USA.
J Chem Phys. 2009 Apr 28;130(16):164313. doi: 10.1063/1.3123808.
First principles studies on the geometry, electronic structure, and magnetic properties of neutral and anionic Fe(2)Si(n), Co(2)Si(n), and Ni(2)Si(n) (1 < or = n < or = 8) clusters have been carried out within a gradient corrected density functional framework. It is shown that these clusters display a variety of magnetic species with varying magnetic moment and different magnetic coupling between the two transition metal atoms. While Fe(2)Si(n) clusters are mostly ferromagnetic with large moments, Ni(2)Si(n) clusters are mostly nonmagnetic. Our studies of the variation of the binding energy upon addition of successive Si atoms and the gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital indicate that many of the motifs are quite stable and could be suitable as building blocks for generating magnetic cluster assembled materials. The studies also reveal motifs that could be used in molecular electronic devices to generate spin polarized currents or large magnetoresistance.
在梯度校正密度泛函框架内，对中性和阴离子型Fe(2)Si(n)、Co(2)Si(n)和Ni(2)Si(n)（1≤n≤8）团簇的几何结构、电子结构和磁性进行了第一性原理研究。结果表明，这些团簇呈现出多种磁性物种，具有不同的磁矩以及两个过渡金属原子之间不同的磁耦合。虽然Fe(2)Si(n)团簇大多具有大磁矩的铁磁性，而Ni(2)Si(n)团簇大多是非磁性的。我们对逐个添加Si原子时结合能的变化以及最高占据分子轨道和最低未占据分子轨道之间能隙的研究表明，许多结构单元相当稳定，可作为构建磁性团簇组装材料的基石。研究还揭示了可用于分子电子器件以产生自旋极化电流或大磁电阻的结构单元。
