纤锌矿结构混晶Al_xGa_(1-x)N中的光学声子和极化子

Optical phonon and polaron in wurtzite Al_xGa_(1-x)N ternary nitride-based crystal

由于声子和极化子对纤锌矿结构混晶和由其组成的量子阱的物理性质存在重要影响,采用赝原胞模型法计算纤锌矿结构混晶中Γ点的光学声子频率与组分x的关系,运用微扰的方法计算纤锌矿结构混晶中极化子有效质量mi*和能量迁移Ei随组分x的变化关系.计算结果表明:纤锌矿结构混晶AlxGa1-xN中的LO声子和TO声子均表现为单模行为,极化子的有效质量mi*和能量迁移Ei随x的变化呈线性变化.

Phonons and polaron play an important role in physical properties of wurtzite ternary nitride-based crystals and quantum well composed of the crystals.The relationship between optical phonon frequencies at Γ point of the crystal and the concentration x is calculated by using the pseudo-unit-cell approach.The relationships of energy shifts and effective masses of a polaron in the system with x are calculated by using the perturbation method.The results show that A1 and E1 branches of optical phonons in wurtzite AlxGa1-xN exhibit one mode behavior,and energy shifts and effective masses of a polaron show approximately a linear relationship with the concentration x.