铁基超导体的多重元素替代：能带填充、电子关联及无序效应对Tc的影响

项目名称： 铁基超导体的多重元素替代：能带填充、电子关联及无序效应对Tc的影响

项目编号： No.11304183

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 王操

作者单位： 山东理工大学

项目金额： 30万元

中文摘要： 元素替代长期以来都是研究超导电性和其他强关联电子系统的重要实验方法。一般情况下，元素替代对物性的影响可以分为两个层面：其一为原子层面，表现为晶体结构的变化和替代缺陷（无序）；其二为电子结构层面，表现为载流子浓度的变化，能带的变化以及与无序相关的电子局域化。对于单一施主的元素替代实验，由于上述多种效应很可能同时对材料的物理性质产生影响，致使难以区分它们在物性演变中所起的作用。本项目的主要目标是在几种主要类型的铁基超导体中，通过综合运用Fe-As层外载流子型元素替代、Fe-As层内同价元素替代以及真空退火等实验方法，相对独立的控制晶体结构的变化、载流子填充水平以及导电层的无序程度，同时研究物理性质和这三者之间的关联，并探索进一步提高铁基超导体转变温度的可能性。

中文关键词： 铁基超导体；元素替代；电子相图；结构设计；

英文摘要： Element substitution is used as one of the most important probe in the study of superconductivity and strongly correlated electron systems. Generally, the substitution effects can be divided into two levels: (1) At the atomic level, it is manifested as the change in crystal structure and the increase in disorder. (2) At the electronic level, it is expressed as the change of the carrier concentration, the variation of the band structure as well as the electronic localization induced by the disorder. When a given atom in the unit cell is partially substituted, all these effects will be introduced into the system simultaneously. It is thus extremely difficult, and indeed in most cases quite impossible for a single-donor element substitution experiment to distinguish between all these effects. In this project, we propose to control the crystal structure, carrier filling, as well as the doping induced disorder of the iron-based superconductors independently via studying the annealing effects together with the co-substitution effects of anisovalent and isovalent elements in the insulating and the conducting layers respectively. In this way, the relationship between superconducting Tc and the above mentioned three type of substitution effects will be clarified. Moreover, efforts will be make to explore the possibility

英文关键词： iron-based superconductors；element substitution；electron phase diagram；structural design；