磷化物三元混晶中电子-声子相互作用的维度和体积效应

考虑电子-声子耦合强度因维度而异,导出了描述三维、二维和一维混晶中电子-声子相互作用的哈密顿量。考虑构成三元混晶的两种二元晶体的晶格失配会使混晶体积随元素组分比改变,在推导三维、二维和一维三元混晶中极化子自陷能量和重整化有效质量时计入了离子相对位移与二元晶体原胞体积的关系。结果表明:磷化物三元混晶中极化子自陷能量和重整化有效质量随元素组分的变化关系呈明显的非线性特征,对晶格适配明显、电子-声子耦合较强的材料,体积效应不可忽略。维度越低,非线性特征和体积效应越明显。

The Dimension and Volume Effects on Electron-Phonon Interaction in Ternary Phosphide Mixed Crystals

The Hamiltonians of electron-optical-phonon interaction between an electron and two branches of LO phonon modes in three-dimensional (3D),two-dimensional (2D) and one-dimensional (1D) ternary mixed crystal (TMC) were derived.Relation of the ionic relative displacement and the lattice mismatch of the two binary crystals were considered in the polaronic energy and effective mass of the ternary mixed crystals.It was verified theoretically that the obvious nonlinearity of the polaronic energy and effective mass varying with the composition of TMC were essential and the unit-cell volume effects could not be neglected except the very weak e-p coupling.The deducting of the dimension of the mixed crystal strengthened the effects of the nonlinearity of the polaronic energy and effective mass,as well as the unit-cell volume effects.