Role of the extra Fe in K_2-x Fe_4+y Se₅ superconductors.

ABSTRACT: The exact superconducting phase of K_2-x Fe_4+y Se₅ has so far not been conclusively decided since its discovery due to its intrinsic multiphase in early material. In an attempt to resolve this mystery, we have carried out systematic structural studies on a set of well-controlled samples with exact chemical stoichiometry K_2-x Fe_4+x Se₅ (x = 0-0.3) that are heat-treated at different temperatures. Using high-resolution synchrotron radiation X-ray diffraction, our investigations have determined the superconducting transition by focusing on the detailed temperature evolution of the crystalline phases. Our results show that superconductivity appears only in those samples that have been treated at

SUBMITTER: Wang CH 

PROVIDER: S-EPMC6347709 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature