特殊材料之第一原理多體計算(I)
學年 92
學期 1
出版(發表)日期 2004-01-01
作品名稱 特殊材料之第一原理多體計算(I)
作品名稱(其他語言) Ab Initio Many-Body Calculations on Novel Materials (I)
著者 薛宏中
單位 淡江大學物理學系
描述 計畫編號:NSC93-2112-M032-014 研究期間:200408~200507 研究經費:1,326,000
委託單位 行政院國家科學委員會
摘要 在本計畫中,我們將進行第一原理量子力學計算法,研究光電半導體(包括III-V 族與 II-VI 族化合物)、奈米管與鈣鈦礦(perovskite)其含雜質系統(缺陷及摻雜)之電子結構與光 學性質。由於密度泛函理論僅限於基態理論,我們將利用密度泛函微擾理論,與準粒子 GW 近似法,計算以上含雜質系統之多體激發態特性。首先,利用線性響應之方法,計 算系統之聲子頻譜(特別是對具鐵電性之鈣鈦礦材料),並進一步通過發展電子-聲子耦合 計算法,得到算相關係統之超導相變溫度Tc;接著,在高效率虛位能GW 計算法下, 我們將研究塊材及奈米系統中之雜質效應,我們也將討論雜質所可能引起之磁性性質; 再者,為了瞭解雜質對材料光學性質的影響,我們將使用準粒子計算結果以解 Bethe-Salpeter 方程式,進行材料之光學計算;更重要的是,本計畫將致力於開發新穎第 一原理多體理論,以更準確地計算凝態材料。 In this project, opto-electric semiconductors (III-V and II-VI compounds), nanotubes and perovskites with impurities (point defects, dopants,etc.) will be studied by ab-initio quantum mechanical calculations on the microscopic level. Regarding the ground-state limitation of density functional theory (DFT), we will perform the both density functional perturbation theory (DFPT) and quasiparticle GW calculation to elucidate the many-body excitation effects in above defect systems. Firstly, using DFPT within the framework of linear response scheme, we will investigate the phonon spectrum of systems (especially in ferroelectric perovskites) and probe the transition temperature Tc by implementing the electron-phonon coupling calculation. Secondly, we will study the defect effects in the compounds and nano-systems with a high-performance pseudopotential GW method, and the possible defect-induced magnetization will be also taken into account. Thirdly, we will carry out a two-particle Green』s function approach (the Bethe-Salpeter equation formalism) to elucidate the optical and excitonic properties of the materials with defects. Most importantly, we will develop novel ab-initio many-body methods in this project in order to do more accurate calculation of condensed matters in the future.
關鍵字 光電半導體;奈米管;鈣鈦礦;密度泛函微擾理論;電子-聲子耦合;虛位能GW 計算法;Bethe-Salpeter 方程式;第一原理多體理論;opto-electric semiconductors;nanotube;perovskite;DFPT;pseudopotential GW;electron-phonon coupling;Bethe-Salpeter equation;ab-initio many-body methods
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