标题： 通过尺寸和单轴应变在纤锌矿结构GaAs纳米线中实现直接-间接带隙转变 显示英文标题

标题： Engineering direct-indirect band gap transition in wurtzite GaAs nanowires through size and uniaxial strain

摘要： wurtzite GaAs纳米线在[0001]方向的电子结构通过第一性原理计算进行了研究。 发现当纳米线的直径小于~28 {\AA }时，GaAs纳米线的带隙会发生从直接带隙到间接带隙的转变。 对于具有间接带隙的薄GaAs纳米线，发现如果施加适度的外部单轴应变，其带隙可以被调节为直接带隙。 拉伸和压缩应变都可以触发间接带隙到直接带隙的转变。 带隙转变的临界应变由导带中两个状态的能量交叉决定。 显示英文摘要

摘要： Electronic structures of wurtzite GaAs nanowires in the [0001] direction were studied using first-principles calculations. It was found that the band gap of GaAs nanowires experience a direct-to-indirect transition when the diameter of the nanowires is smaller than ~28 {\AA}. For those thin GaAs nanowires with an indirect band gap, it was found that the gap can be tuned to be direct if a moderate external uniaxial strain is applied. Both tensile and compressive strain can trigger the indirect-to-direct gap transition. The critical strains for the gap-transition are determined by the energy crossover of two states in conduction bands.