DFT+Gutzwiller方法研究过渡金属氧化物

项目名称： DFT+Gutzwiller方法研究过渡金属氧化物

项目编号： No.11274095

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 王广涛

作者单位： 河南师范大学

项目金额： 78万元

中文摘要： 过渡金属氧化物因为表现出超导、庞磁阻、Mott金属绝缘体相变、重费米子行为、 Kondo效应等，一直是凝聚态物理的研究热点。同时，因为过渡金属氧化物中关联效应非常明显，这也是计算凝聚态物理的难点。 针对这个难题，我们在物理所方忠研究员领导下发展了能很好处理从强关联到弱关联体系整个区域与电子关联效应相关物理问题的DFT+Gutzwiller方法。我们将用该方法研究：1.Fe基超导体中的轨道波动对声子软化和磁矩等影响；2.新合成的 KCrF3 中关联效应和Jahn-Teller畸变导致的轨道和磁有序等问题；3.Ca2-xSrxRuO4等材料的金属-绝缘体相变问题。要解决上述问题就必须考虑关联效应导致的能带重整和轨道波动等问题，这是目前流行的LDA+U方法所不能处理的。LDA+DMFT方法虽能处理关联体系，但计算量太大，无法处理复杂的真实材料，而DFT+Gutzwille方法能够兼顾效率和准确。

中文关键词： 过渡金属氧化物；铁基超导体；磁有序和轨道有序；热电材料；拓扑材料

英文摘要： Transition metal oxides(TMO) have been the research focus of condensed matter physics, since they show superconductivity, colossal magnetoresistance, Mott metal-insulator transition, heavy fermion behavior, Kondo effect. At the same time, it is a knotty issue because that the correlated effect is very important in the TMO systems. To resolve this problem, we developed the DFT+Gutzwiller method,under the leadership of Fang Zhong.Our method can solve the above problem in the whole range from weak to strong correlated systems.We will use this method to study the followning three issues. Firstly, we will study the multiorbital nature of iron pnictides superconductors. The superconducting iron pnictides are interesting because of their different aspects to the cuprates:(1)they are multiorbital systems, where spin, orbital, and charge degrees of freedom are all active, while in cuprates an effective single band model can be established;(2)the electron correlation strength is intermediate, not as strong as that in cuprates. Due to the multiorbital nature, where interorbital interaction becomes important, the correlation in iron pnictides still plays a crucial role in determining not only the correct internal structure but also the correct electronic structure near the Fermi surface. Secondly, we will study the orbital

英文关键词： Transition metal oxides；Fe-based superconductors；Magnetic and orbital ordering；thermoelectric materials；Topological materials