B_xGa_(1-x)As合金电子结构与光学性质的第一性原理计算（英文）

First-Principles Study of Electronic and Optical Properties of B_xGa_(1-x)As Alloy

基于密度泛函理论的第一性原理和特殊准随机近似方法,建立64原子的超胞并且对结构进行几何优化.计算和讨论具有闪锌矿结构的三元合金BxGa1-xAs的结构参数、电子结构和光学性质.结果表明:BxGa1-xAs的晶格常数与使用Vegard定理计算得到的值有微弱的偏离,键长存在明显的弛豫;计算得到的合金带隙弯曲参数变化较小(2.57 eV-5.01 eV)而且对组分变化的依赖很弱;最后分析硼的并入对GaA s光学参数包括介电函数、反射率、折射率、吸收系数和能量耗散函数的影响.

First-principles calculations based on density functional theory are performed for zinc-blende BxGa1-xs alloy with a special quasirandom structure （SQS） approach in a 64-atom supercell. Structural, electronic and optical properties of BxGa1-xAs alloy are comprehensively investigated under optimized geometry structures. It was found that calculated lattice constant slightly deviated from Vegard＇s law and significant bond length relaxation is shown. Calculated bowing parameters of energy gap are small （2.57 eV - 5.01 eV） and are weakly composition-dependent. Finally, effects of boron composition on optical parameters including dielectric function, reflectivity, refractive index, absorption coefficient and energy loss function are analyzed in detail.