Application of the First-Principles Molecular Dynamics Method to the Study of Condensed Matter Physics under High Pressure

第一性原理分子动力学方法在高压凝聚态物理研究中的应用

• 批准号: 08454105
• 负责人: TSUNEYUKI Shinji
• 金额: $ 4.8万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454105/
• 关键词: First-Principles Moleculara Dynamics Method; High Pressure; Diamond; BCN Copmound; C60 Polymer; Fullerene; Silicide; SnI_4; ヘテロダイヤモンド; C_<60>ポリマー; SnI4; グラファイト; 構造相転移; 層状物質

High-pressure experiment has playd important role not only in fundamental research of condensed matter physics and geophysics but also in applications for synthesizing metastable crystals inaccessible at ambient pressure. In-situ obsesrvation of a small amount of specimen at ultra high pressure is, however, very difficult in general, so that theoretical suppport by computer simulations is getting morre and more important. This work aim at establishing the method of predicting crystal structures and electronic properties of materials under high pressure independently of experiments by introducing the constant pressure scheme into the traditional formalism of the First-Principles Molecular Dynamics (FPMD) method.We developed a parallelized computer code of the FPMD method with the conjugate-gradient technique for optimizing electronic structure. We also devised a new method of searching for the transition state of structural transformataion or chemical reaction processes. This computer code has been used for investigation of the following problems :(1) Comparison of the activation energies for graphite-to-c-diamond and graphite-to-h-diamond structural transformations(2) Material design of BCN heterodaimond, that is, prediction of the probable structures and their properties, and also proposal of synthesis paths(3) Structural optimization and large-scale band calculation of alkali-doped C60-polymers(4) Pressure dependence of the stability of polymorphs of CaSi_2(5) Search for probable structures of the high-pressurer atomic phase of SnI_4

高压实验不仅在凝聚态物理和地球物理的基本研究中，而且在合成在环境压力下无法访问的亚稳态晶体的应用中都具有重要作用。但是，在超高压下少量标本的原位观察到非常困难，因此计算机模拟的理论支持变得越来越重要，而且越来越重要。这项工作旨在建立通过将恒定压力方案引入第一原则分子动力学（FPMD）方法的恒定压力方案（FPMD）方法的高压下预测材料的晶体结构和电子性能的方法。我们开发了一种通过fpmd方法的平行计算机代码，该法代码fpmd方法是通过使用fpmd方法来优化电子结构的。我们还设计了一种新的方法来搜索结构转化或化学反应过程的过渡状态。该计算机代码已用于调查以下问题：（1）比较石墨至C-二甲蒙德和石墨至H-二摩德结构转换的激活能（2）BCN Heterodaimond的材料设计，即可能的结构及其性质的预测，以及对结构的组合路径的提议（3）结构的序列（3）allscale Carcutuntial Carcutuntial Carcutuntial Carcutuntion Carcutuntial Carcutuntial Carcutuntial Carcutution Calcutution calcale calcale carkale calk。 C60聚合物（4）CASI_2（5）搜索SNI_4高压原子相的可能结构的稳定性的压力依赖性

项目成果

S.Tsuneyuki, T.Ogitsu, Y.Tateyama, K.Kusakabe and A.Kikuchi: "Possible Synthesis of Heavily Doped Diamond from Li Intercalated Graphite" in Advances in High Pressure Research in Condensed Matter (NISCOM,New Delhi, India, 1997). 104-108 (1997)

S.Ttsuneyuki、T.Ogitsu、Y.Tateyama、K.Kusakabe 和 A.Kikuchi：“Possible Synthesis of Heavily Doped Diamond from Li Intercalated Graphite”，《凝聚态高压研究进展》（NISCOM，印度新德里，1997 年）

K.Kusakabe: "'Can Corrugated Si-Planes of CaSi_2Flatten under High Pressure?'" Proc.of Int Conf.on High Pressure Science and Technology(1997,Kyoto). in press.

K.Kusakabe：“Can Corrugated Si-Planes of CaSi_2Flatten under HighPressure?”Proc.of Int Conf.on HighPressure Science and Technology（1997，京都）。

Y.Tateyama: ""Proposed synthesis path for heterodiamond BC_2N"" Physical Review. B55. R10161-R10164 (1997)

Y.Tateyama：“异质金刚石 BC_2N 的拟议合成路径”物理评论。

Y.Tateyama: ""Electronic States of BC_2N Heterodiamond(111)Superlattices"" Proceedings of International Conference on Silicon Carbide, III-nitrides and Related Materials-1997,. (in press.). 1

Y.Tateyama：“BC_2N Heterodiamond(111)Superlattices 的电子态””碳化硅、III族氮化物及相关材料国际会议记录-1997年，。

S.Tsuneyuki: "'Possible Synthesis of Heavily Doped Diamond from Li Intercalated Graphite'" in Advances in High Pressure Research in Condensed Matter(NISCOM,New Delhi,India,1997). 104-108 (1997)

S.Ttsuneyuki：“‘Possible Synthesis of Heavily Doped Diamond from Li Intercalated Graphite’”，《凝聚态高压研究进展》（NISCOM，印度新德里，1997 年）。