Electronic Structure Calculation of Condensed Matters by the First Principle

首先，原理电子结构计算对于研究具有未知性质的新凝聚态物质具有重要意义。本课题组的研究目标是发展新的强有力的第一性原理电子结构计算方法及其在几种材料中的应用。本项目的具体研究主题如下：(I)多重LMTO方法和GW近似的发展及其在过渡金属中的应用。(Ii)LDA+U方法及其在过渡金属氧化物(如锰和镍钙钛矿化合物)中的应用，并讨论其磁性结构。(Iii)现实凝聚体系中的量子蒙特卡罗计算。例如水分子的二聚体稳定和氢键。(IV)第一原理分子动力学中阶数N方法的发展。(V)第一原理分子动力学中的有效模拟方法，包括高温和其他极端条件下的复杂液体。(VI)准晶中的反常电子输运。对于新材料中的电子结构计算，发展几种方法并同时使用它们是非常必要的，因为任何一种计算方法并不总是对所有感兴趣的系统都有用，因为它需要计算机内存大小和CPU时间。

First principle electronic structure calculations is of great importance to investigate new condensed matters with exotic properties not known before. Research of our group aims to develop new powerful methods of the first principle electronic structure calculations and their applications to several materials.Concrete research theme of our project is as follows :(i)Developement of multiple-LMTO methods and the GW approximation with applications to transition metals.(ii)LDA+U method and applications to Transition Metal Oxides, e.g.Mn and Ni perovskite compounds and discussed their magnetic structures.(iii)Quantum Monte Carlo calculations in realistic condensed systems, e.g.dimer stabilization of water molecules and hydrogen bonds.(iv)Developement of Order-N method in first principle molecular dynamics.(v)Efficient simulation methods in first principle molecular dynamics for condensed systems, including complex liquids at elevated temperatures and with other extremum conditions. Applications may be forwarded to NaSn which shows and exotic transport property in the high temperature solid phase.(vi)Anormalous electronic transport in quasicrystals.For the electronic structure calculations in new materials, it is very essential to develope several methods and use them simultaniously, because any calculating method is not always useful for all interesting systems, due to its required computer memory size, cpu time.