稀土三氢化物高压下的金属-绝缘体相变与超导相变研究

项目名称： 稀土三氢化物高压下的金属-绝缘体相变与超导相变研究

项目编号： No.11464005

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 孔博

作者单位： 贵州师范学院

项目金额： 48万元

中文摘要： 本项目以含强局域4f电子的稀土三氢化物ReH3（Re=Sm,Gd,Tb,Dy,Ho,Er,Lu)为研究对象，对它们高压下的金属-绝缘体相变与超导相变开展研究工作。通过LDA+U，HSE03+U等来处理4f电子的强关联效应，在这基础上采用多体微扰理论GW方法对kohn-sham 方程进行修正，以解决常规DFT计算带隙被严重低估甚至不能打开的问题，进而探索稀土三氢化物磁态、不同的强局域f电子、不同位置的氢缺陷与氢缺陷浓度对带隙起源、金属-绝缘体相变及其它物理性质的影响。另一途径是基于密度泛函理论的动力学平均场理论(DFT+DMFT），在DMFT部分来实现f电子的强相关效应，采用LDA+DMFT计算稀土三氢化物的能量，电子结构，光谱函数等, 并与第一性原理计算的结果及实验进行比较分析。高压超导相变温度研究，将采用最主流的密度泛函线性微扰理论（DPFT），以探究这些化合物在压强下的超导行为及规律。

中文关键词： 第一性原理计算；高压相变；金属-绝缘体相变；超导相变；多体效应

英文摘要： The research objects of the project are rare-earth trihydridies ReH3(Re=Sm,Gd,Tb,Dy,Ho,Er,Lu)which contain strongly located 4f electronics,we are going to focus our work and research on their metal-insulator phase transitions and supercondoucting phase transitions under pressure. The strongly correlated effect of 4f electronics are considered via LDA+U, HSE03+U, and so on;based on these caculations,we will adopt many-body perturbation theory-GW method to correct kohn-sham equation,so that the conventional problem that band gap cann't be opened or is underestimated seriously is to be solved;furtherly, the effects of the magnetic states,different strongly located 4f electronics,different sites H defects and H defects concentration on the origin of band gap, metal-insulator phase transition and other physics properties about lanthanide trihydridies will be explored. The other way is to combine dynamical mean field theory (DMFT) with electronic structural calculations based on density founction approximation,the local correlation effect will be described by dynamical mean field theoy(DMFT);the energy,electronic structure, spectral founction will be caculated via LDA+DMFT, the results will be compared and analyzed with the results of first-principles caculations or experiments. The studies of supercondoucting phase transition temperatures of these rare-earth trihydridies under pressure will be carried out by density functional linear-response theory， their superconducting behaviors and supercondoucting phase tansition law will be explored and discussed.

英文关键词： First-principles calculations;High pressure phase transition;Metal-insulator phase transition;Superconducting phase transition;Many-body effects