不同温度硅纳米薄膜在表面重构下杨氏模量的分子动力学研究

Molecular Dynamics Study on Young＇s Modulus of Silicon Nanofilms Under Surface Reconstruction at Finite Temperature

采用分子动力学方法计算了100K到800K之间（001）面硅纳米薄膜（1nm，2nm厚）[110]与[1—10]两个方向上的杨氏模量。2×1表面重构形成了dimmer键，使[110]方向杨氏模量大于[1—10]方向杨氏模量。纳米薄膜的杨氏模量随着温度升高而下降。热膨胀导致了温度效应。当尺度到达纳米尺度，表面重构和温度效应更加明显。

In this paper, we investigate Si （001） nanofilms （1nm and 2nm thickness） Young＇s modulus under （2×1） surface reconstruction along [110] and [1-10] directions at different temperature from 100K to 800K by Molecular dynamics （MD） is investigated. The （2xl） surface reconstruction leads to formation of dimmers, making Young＇s moduli along the [110] direction stiffer than the [1-10] direc- tion. Young＇s moduli decrease as temperature increases. Thermal expansion cause temperature effect . Surface reconstruction and temperature effect are more significant as size is scaled down to nanoscale .