Approach to the Iron-based Superconductivity through Neutron Scattering on Separate Dimensional Materials

Abstract

Since the discovery, research on iron-based superconductivity (SC) has become one of main streams in condensed matter physics. The interplay between structure, magnetism and SC is one of most intriguing subjects of this field. To gain further insight into the mechanism of the SC and variation of magnetic orders, investigation of Fe-based compounds with a separate spatial dimension is important. This is because the dimensionality should influence magnetism and can control itinerancy of electrons by changing Fermi surface topology. Here we report our recent studies of iron-based two-leg ladder compounds AFe₂X₃ (A = Rb, Cs, Ba; X = S, Se). Unlike most of parent compounds of the Fe-based SCs, the ladder compounds are insulating down to low temperatures. Through bulk properties and neutron diffraction measurements, a variety of magnetic structure and low-dimensional characteristics were elucidated. These would provide a clue for understanding of the iron-based SC.