氢化与非氢化石墨烯纳米条带的密度泛函研究

基于密度泛函理论的第一性原理计算方法,研究了宽度N=8的边缘氢化和非氢化条带的结构和电子性质. 研究表明,扶手形无氢化石墨纳米条带的边缘碳原子是以三重键相互结合,它在边缘的成键强度比氢化时要高,具有更强的化学活性,可作为纳米化学传感器的基础材料. 能带结构计算表明,无论是扶手形条带还是锯齿形条带,它们都是具有带隙的半导体,且无氢化条带的带隙要比氢化的条带带隙宽度大,氢化对于条带的电子性质具有显著修饰作用. 通过锯齿形石墨纳米条带顺磁性、铁磁性和反铁磁性的计算,发现反铁磁的状态最稳定,并且边缘磁性最强,这有利于条带在自旋电子器件中的应用. 关键词： 石墨纳米条带 成键机理 电子结构 自旋分布

Density functional study on hydrogenation and non-hydrogenation graphene nanoribbon

Based on density functional theory and first-principles method, we investigate the structure and the electronic property of graphene nanoribbion with width N=8 and with or without hydrogen saturation on their edge. Our results show that the carbon atoms on the edge of armchair graphene nanoribbon without the hydrogen saturation are bonded together by triple bonding, which is stronger and more sensitive than that in the case of hydrogen saturation. This type of graphene nanoribbon can serve as a kind of basic material for nano-sensor. Our band structure calculations indicate that both armchair and zigzag nanoribbions are of semiconductor possessing an energy gap. Furthermore, the energy gap of nanoribbon without hydrogen saturation is larger than that with hydrogen saturation, which implies that hydrogen saturation has distinct decoration to the property of the nanoribbon. By the calculation of the paramagnetism, ferromagnetism and anti-ferromagnetism states of the zigzag graphene nanoribbon, we find that anti-ferromagnetism state is the most stable among them, and its magnetism on the edge is strongest, which is suitable for the application in spinelectronics.