导线非共线的分子器件输运性质的第一性原理研究

First-principles study on transport property of molecular device with non-collinear electrodes

分子器件是电子器件向小体积化发展的极限,分子器件中的电子在输运过程中体现出明显的量子效应,分子导线与分子接触的位置和导线间的角度等器件结构因素都会对分子器件的输运性质产生较大的影响.迄今为止,尚未见利用第一性原理量子输运计算方法研究导线非共线的分子器件输运性质的报道.本文以金-苯(硫醇)-金结构的分子器件为例,利用基于非平衡格林函数理论和密度泛函理论的第一性原理量子输运计算方法对其输运性质进行了系统研究,特别注重于研究随着非共线导线间导线夹角角度的变化及导线和苯(硫醇)分子接触位置的不同对器件输运性质的影响.计算表明,金导线与苯(硫醇)的接触位置及导线的夹角等器件结构细节不仅能够定量地影响金-苯(硫醇)-金分子器件的电流大小,还能够定性地改变器件的输运性质,使得部分器件结构出现负微分电阻效应.研究结果对全面理解分子器件的输运性质具有一定的指导意义.

Molecular device is the ultimate electronic devices in the view point sense of scale size. Electron transport in molecular device shows obvious quantum effect, and the transport property of molecular device will be strongly affected by the chemical and structural details, including the contact position and method between the molecule and electrodes the angle between two electrodes connecting to the molecule. However, we notice that in the existing reports on device simulations from first principles the two electrodes are always in a collinear case. Even for multi-electrode simulations one usually used to adopt orthogonal electrodes, namely, each pair of the electrodes is in a collinear case.