扶手椅型石墨烯纳米带在单轴应力下的能隙调控

利用紧束缚方法研究了扶手椅型石墨烯纳米带沿其长度方向受单轴应力的电子能谱及能隙与形变量的关系.结果表明:在一定的应力下,3m和3m+1型纳米带的能隙随纳米带宽度的变化呈现零能隙拐点,而这种拐点随着非近邻项的逐渐计入向着纳米带宽度窄的方向移动.当带宽较窄时,无论非近邻项是否计入,除了3m+2外,只有3m的三近邻情形能隙与形变量(小形变)的曲线才有拐点;随着宽度的增加,除了3m+1的最近邻情况外,3种宽度3m,3m+1和3m+2都出现零能隙拐点.

Energy-gap control of armchair graphene nanoribbons under uniaxial strain

The electronic energy spectrum and energy gap of armchair graphene nanoribbons under uniaxial strain along the length direction of the ribbon were studied by using the tight-binding approach.When the strain was fixed,for widths 3m and 3m＋1,the change of the energy gaps with the width of the nanoribbon showed the inflexion points of zero energy gaps and the points moved toward the small width as the non-neighbor hopping was taken into account gradually.When the width was narrowed,whether the non-neighbor hopping was included or not,there was inflexion point when the third neighbor was included for width 3m apart from 3m＋2.But the inflexion points appeared as increasing of the widths apart from the nearest neighbor of width 3m＋1.