Crystal and magnetic structures of Fe 1+y (Te,Se)

1. CAREER: Superconductivity and magnetism of Iron chalcogenidesZhiqiang Mao, Tulane University, DMR 0645305 The discovery of superconductivity in iron pnictides has generated tremendous excitement [1].Iron chalcogenide is the simplified version of Fe-based superconductors; understanding of the superconducting properties of this system has been considered critical [2]. Iron chalcogenide FeSe was first discovered to be superconducting by M.K. Wu’s group [3]. Mao’s group studied the Fe1+y(Te,Se) system and found that the superconductivity of this system is also close to a magnetic instability [4]. Mao’s group also conducted neutron scattering studies on the Fe1+y(Te,Se) superconductor system in collaboration with Bao et al [5,6]. Their work revealed that the antiferromagnetic (AFM) order in the non-superconducting parent compound Fe1+yTe propagates along the diagonal direction of the Fe square lattice and can be tuned from commensurate to incommensurate one by changing Fe stoimechiometry, in sharp contrast with the commensurate Fermi surface nesting-driven AFM order along the edge of the Fe square lattice seen in iron pnictides [7,8,9]. These results have generated an important impact in the field since they suggest a distinctive form of superconducting pairing mediated by magnetic spin fluctuations. Crystal and magnetic structures of Fe1+y(Te,Se) M.H. Fang et al., Phys. Rev B 78, 224503 (2008) (selected to Editor’s suggestion). W. Bao et al., Phys. Rev. Lett.102, 247001 (2009). Y.M. Qiu et al., Phys. Rev. Lett. 103, 067008 (2009).

2. CAREER: Superconductivity and magnetism of Iron chalcogenidesZhiqiang Mao, Tulane University, DMR 0645305 I have implemented several measures to integrate my research into my teaching. 1. Developing new courses I have developed two new courses in terms of my research: “Introduction to exciting areas in materials science” and “Electronic properties of materials”. The “Introduction to exciting…” course is offered to undergraduate freshmen and is aimed at providing an environment for interdisciplinary learning. The “Electronic properties of materials” course is offered to graduate and senior undergraduate students. The emphasis of this course is placed on microscopic understanding of the electronic and magnetic properties which are most relevant to modern device applications. Both courses include Lab components. Some labs were designed in terms of my research projects. I have received very high evaluations from students for both courses. Many of them mentioned in their evaluation that teaching integrated with research, like in this course, is truly effective in learning. 2. Providing special colloquia for non-physics undergraduate students In teaching General Physics course, I offered some special colloquia to introduce the science related to my research projects. To make the colloquia more accessible to those non-physics undergraduate students, I did some interesting experimental demonstrations such as the Meissner effect of superconductors and single crystal growth of oxide materials. Such colloquia were very successful and attracted a good deal of attention from students. 3. Involving students in the research as participants. Research training is also an important part of this project. Two postdocs, six graduate students, and one undergraduate student have been involved as participants in the research supported by this project; three of these students are female.