【摘要】 在修正的随机元素等位移-MREI模型的基础上建立了一个新模型,计算了AB1-xCx型Ⅲ-Ⅴ族半导体混晶的长波长光学声子模频率的组分变化关系。模型中假设次邻力常数远小于近邻力常数,同时,运用离子晶体结合的重叠排斥能,估算出两个近邻力常数随组分x呈负幂指数变化,而非常规的线性变化。最后比较了AsAl1-xGax、GaP1-xAsx和SbAl1-xGax三种混晶的理论结果和实验数据,两者符合较好。更多还原

【Abstract】 On the basis of the modified random element isodisplacement (MREI) model, a new model is set up. The dependence between the long-wavelength optical phonon frequencies and the composition of mixed crystals XB1-xCx belonged to Ⅲ-Ⅴ semiconductors is calculated. The second neighbor force constants are assumed to be far less than the first ones. Instead of a linear variation, the two first neighbor force constants can be evaluated to be a negative exponent variation with the composition, using the overlapped repulsive potential of the ion crystal combination. At last the calculated result of three mixed crystals, AsAl1-xGax, GaP1-xAsx and SbAl1-xGax, is found to be in good accordance to the experiments.更多还原