论文部分内容阅读
利用微扰－变分法研究了极性三元混晶中束缚在浅库仑杂质中心的极化子．采用改进的无序元胞独立位移模型和有效声子模近似，计及电子和两支光学声子的相互作用，导出了极化子基态能量和束缚能量随组分变化的解析解，分析了声子屏蔽、质量重整化和自陷效应．对若干三元混晶的数值计算结果表明：声子屏蔽效应占主要作用；电子声子的相互作用减小了束缚极化子的束缚能．发现声子对束缚能的贡献随组分的变化是非单调的．讨论了有效声子模方法的有效性和适用范围
The perturbation - variational method was used to study the polarons bound to the shallow Coulomb impurities in polar ternary mixed crystals. An improved unoriginal cellular independent displacement model and an effective phonon mode approximation are used to account for the interaction between the electron and the two phonons. The analytic solutions of the ground state energy and the binding energy of the polaron with the change of the composition are derived. Phonon shielding, mass renormalization and self-trapping effects. The numerical results of several ternary mixed crystals show that the phonon shielding effect plays a major role, and the interaction of the electronic phonons reduces the binding energy of the bound polaron. The contribution of phonons to the binding energy is found to be non-monotonic with variations in composition. The validity and applicability of effective phonon modes are discussed