Correct Evaluation of the Effect of Transverse Effective Charges on Phonons in AlAs Quantum Dots  

作　　者：QINGuo-Yi 

机构地区：[1]DepartmentofPhysics,NanjingUniversity,Nanjing210093,China

出　　处：《Communications in Theoretical Physics》2003年第6X期727-734,共8页理论物理通讯（英文版）

基　　金：国家重点基础研究发展计划(973计划)，国家自然科学基金

摘　　要：An improved valence force field model (VFFM) is suggested to calculate the phonon modes in both bulk specimens and quantum dots (QDs) of AlAs taking account of the effect of transverse effective charges (TCs) correctly.The resultant dispersions of AlAs bulk phonons are in accord better with the results carefully fitted to the experimental data by using 11-parameters rigid-ion model, than those got by ordinary VFFM, especially in the region of near F point. For AlAs QDs, TCs are evaluated bond by bond for each phonon mode of QD and its effect on the change of the force on atoms is taken into account to modify further the phonon spectrum. The frequency spectra and densities of phonon states of different irreducible representations calculated by using improved VFFM are compared with the results of ordinary VFFM. The correct evaluation of the TCs is not only important in calculating the phonon spectrum of both bulk and QD specimens accurately, but is also in the further discussion of the electron-phonon (e-ph) interaction, which can be directly related to TCs of ions in QD.

关 键 词：量子点 半导体材料 砷化铝 声子模式 横向有效电荷 声子谱 

分 类 号：O471.1[理学—半导体物理]