以第一原理計算分析砷化鎵與磷化銦 紅外線雙聲子特徵譜線之研究

Abstract

我們使用密度泛函微擾理論(Density functional perturbation theory) 作自洽計算來分析雙聲子過程(two-phonon process) 對於砷化鎵以及磷化銦在紅外線特頻譜的貢獻，這些特徵譜線可以藉由連結實驗特徵峰值與雙聲子聯合能態密度(two-phonon joint density of states) 中的范霍夫奇異點(van Hove singularity) 來完成標記，而我們也分析了在第一布里淵區(first Brillouin zone) 中的相關臨界點(critical points)。我們發現砷化鎵以及磷化銦所有的臨界點都只會分布在對稱點Γ, X, L, W ; 對稱軸Σ, Λ, Δ, Q, S; 或是對稱面ΓKL, ΓXWK, ΓXUL。

We perform a self-consistent calculation based on the density functional perturbation theory to analyze the infrared spectral features of GaAs and InP contributed by two-phonon processes. Assignment of the features is made by connecting the experimental spectral peaks to the calculated Van Hove singularities of two-phonon joint density of states. The associated critical points in the first Brillouin zone are analyzed. We find that most critical points of GaAs and InP are located at symmetry points of Γ, X, L and W, symmetry lines of Σ, Λ, Δ, Q, and S, or symmetry faces of ΓKL, ΓXWK and ΓXUL.