Iron-based High Tc Superconductor

Date :From 2009-05-18 To 2009-06-05
Advisory committee :
Local coordinators :Xi Dai,Zheng-Yu Weng,Tao Xiang,Yue Yu
International coordinators :Chang-De Gong,Dung-Hai Lee,Xiao-Gang Wen,Zheng-Yu Weng,Zhong-Xian Zhao

Ever since the discovery of the cuprates, high-Tc superconductivity has been one of the most intensively researched problems in condensed matter physics. Due to such research, new theoretical concepts have been formed, new experimental techniques have been developed, and new materials have been fabricated. The recent discovery of high-Tc superconductivity in the iron-oxypnictides such as LnO1-xFxFeAs, La1-xSrxOFeAs, and Ba1-xKxFe2As2 has lunched a second wave of excitement in this field. Judging from the initial evidences, there are interesting similarities and differences between the iron-oxypnictides and the cuprates. For example, in both systems superconductivity occurs in two dimensional planes containing transition metals. Another similarity is the fact that the stoichiometric compounds are both antiferromagnetic, and upon doping the magnetic order is replaced by superconductivity. On the other hand, there are also important differences. The first is the fact that the stoichiometric parent compounds of the iron-oxypnictides remain kind of metallic rather than Mott insulating. The second difference is that the cuprates are single band systems, while the iron-oxypnictides have multi bands and multi Fermi surfaces. The last, but not the least, is the fact that unlike the cuprates the new superconductor is not a doped spin ½ system. In view of these similarities and differences, it is reasonable to anticipate that an in-depth study of the FeAs-based materials will not only enable us to understand the origin of superconductivity in the new superconductor, but also will sharpen our thinking about the cuprates. Furthermore, the iron based superconductors may also bring the LDA band structure method to a new level.

The goal of the research on the iron-based superconductor can be summarized by “new material, new phenomenon and new mechanism”. This requires collaboration among material scientists and experimental and theoretical condensed matter physicists. The purpose of this rapid response KITPC program is to create an environment for such collaboration. Given the fact that many of the important recent works in the iron-oxypnictides are done in China, we expect this workshop to be a perfect fit of the goal of KITPC.