新型高温超导候选材料Sr_2CuO_2Fe_2As_2的设计及物性研究

Designing and physical property research of Sr_2CuO_2Fe_2As_2:a new candidate for high-Tc Superconductors

基于现有铜氧化物和铁基两类高温超导体的特性,设计了同时包含CuO2层和Fe2As2层的新材料Sr2CuO2Fe2As2,采用第一性原理方法对其进行了稳定性分析,并计算了母体材料及掺杂后的电子能带结构.结果表明,该物质在能量上处于有利地位,具有良好的稳定性.其电子结构与铁基超导体较为相似,表现出弱金属性,其导电性主要集中在Fe2As2层.空穴掺杂时,CuO2和Fe2As2层层间关联得到削弱,材料的导电性仍由Fe2As2层主导;而在电子掺杂中,不仅Fe2As2层的导电性出现增强,CuO2层的导电能力也大幅度提高.结果表明,所设计的Sr2CuO2Fe2As2的电子结构与两类高温超导体具有相似性,可能成为超导候选母体材料,并具有实验研究和理论分析价值.

Based on the characteristics of two series of high-Tc superconductors（HTSCs）-copper oxides and iron-based superconductors, we designed new material Sr2 CuO2 Fe2 As2 , which contain both CuO2 and FeAs layers. After that, using first-principles method we analysized its stability and calculated its electronic structure, and we also calculated the electronic structure when it was doped. It is found that Sr, CuO2Fe2As2 have a stable structure and exhibits weak metallicity. Its electronic structure behaves similar to the one of iron-based superconductors, which indicates the carriers are from FeAs layer. When in the case of hole doping, the interlayer correlation between CuO2 and FeAs layer has been weakened, and the carriers are still from Fe2 As2 layer. While in the case of electron doping, when the conductivity of Fe2As2 layer increases the one of CuO2 layer is also enhanced. It indicates that the new material Sr2CuO2Fe2As2 may be a candidate for superconductors and deserves our research.