Uniaxial strain-induced mechanical and electronic property modulation of silicene.

We perform first-principles calculations of mechanical and electronic properties of silicene under uniaxial strains. Poisson's ratio and the rigidity of silicene show strong chirality dependence under large uniaxial strains. The ultimate strains of silicene with uniaxial strain are smaller than those with biaxial strain. We find that uniaxial strains induce Dirac point deviation from the high-symmetry points in the Brillouin zone and semimetal-metal transitions. Therefore, no bandgap opens under the uniaxial strain. Due to its peculiar structure and variable sp3/sp2 ratio of the chemical bond, the deviation directions of Dirac points from the high-symmetry points in the Brillouin zone and variation of Fermi velocities of silicene exhibit significant difference from those of graphene. Fermi velocities show strong anisotropy with respect to the wave vector directions and change slightly before the semimetal-metal transition. We also find that the work function of silicene increases monotonously with the increasing uniaxial strains. 61.46.-w; 62.20.D-; 73.22.Dj

我们对单轴应变下硅烯的力学和电子性质进行了第一性原理计算。在大的单轴应变下，硅烯的泊松比和刚度表现出强烈的手性依赖性。单轴应变下硅烯的极限应变小于双轴应变下的极限应变。我们发现单轴应变会导致狄拉克点偏离布里渊区的高对称点以及发生半金属 - 金属转变。因此，在单轴应变下没有能隙打开。由于其特殊的结构以及化学键的可变sp³/sp²比例，硅烯的狄拉克点偏离布里渊区高对称点的方向以及费米速度的变化与石墨烯表现出显著差异。费米速度相对于波矢方向呈现出强烈的各向异性，并且在半金属 - 金属转变之前变化很小。我们还发现硅烯的功函数随着单轴应变的增加而单调增加。 61.46.-w；62.20.D -；73.22.Dj（这部分可能是一些分类代码之类的内容，不太确定在这个语境下是否有特殊含义，如果有更多相关信息可进一步准确翻译这部分）