GaAs和AlAs光学声子形变势的第一性原理研究

FIRST PRINCIPLE STUDY OF OPTICAL-PHONON DEFORMA-TION POTENTIALS ON *-AXIS FOR GaAs AND AlAs

本文以冻结声子近似模型,采用空球随原子球位移的冻结势近似的LMTO-ASA计算方案,研究了GaAs和AlAs布里渊区Λ轴的光学声子形变势的计算,得到Γ点和Λ轴光学声子形变势d_0,d_(30),d_(10)(val)和d_(10)(comd)的第一性原理的计算结果。研究中着重从GaAs和AlAs的Λ轴光学声子形变势随k点的变化趋势,从光学声子形变势在Γ点附近满足的关系,以及从不同计算方法对d_0的计算结果与实验结果的比较中,多方面地验证了本方法及其结果的合理性。

Ab initio calculations of optical-phonon deformation potentials (ODP)d_(30), d_(10), (val) and d_(10) (cond) on A-axis in Brillioun zone for the compounds GaAs and AlAs are reported. The study is based on a frozenphonon model and using the LMTO-ASA method with a frozen-potential approximation, in which the displacement of the empty sphere was considered ^+o match its atomic sphere partners. The validity of our method and results have been verified with the aid of calculations for wave-vector dependence of the ODPs on Λ-asix, the numerical test to the expressions about d0 VS d_(30) and d_(10)VS d_(10) (val) near Γ point and an extensive comprison with various calculations as well as the experiment.