Crystal Structure and Superconductivity at about 30 K in $A$Ca$_2$Fe$_4$As$_4$F$_2$ ($A$ = Rb, Cs)

Zhi-Cheng Wang; Chao-Yang He; Zhang-Tu Tang; Si-Qi Wu; Guang-Han Cao

doi:10.1007/s40843-016-5150-x

paper

Crystal Structure and Superconductivity at about 30 K in $A$ Ca $_{2}$ Fe $_{4}$ As $_{4}$ F $_{2}$ ( $A$ = Rb, Cs)

arXiv:1704.01051 · doi:10.1007/s40843-016-5150-x

Abstract

We have synthesized two iron fluo-arsenides $A$ Ca $_{2}$ Fe $_{4}$ As $_{4}$ F $_{2}$ with $A$ = Rb and Cs, analogous to the newly discovered superconductor KCa $_{2}$ Fe $_{4}$ As $_{4}$ F $_{2}$ . The quinary inorganic compounds crystallize in a body-centered tetragonal lattice with space group I4/mmm, which contain double Fe $_{2}$ As $_{2}$ layers that are separated by insulating Ca $_{2}$ F $_{2}$ layers. Our electrical and magnetic measurements on the polycrystalline samples demonstrate that the new materials undergo superconducting transitions at Tc = 30.5 K and 28.2 K, respectively, without extrinsic doping. The correlations between Tc and structural parameters are discussed.

9 pages,4 figures, 1 table

Crystal Structure and Superconductivity at about 30 K in ACa2​Fe4​As4​F2​ (A = Rb, Cs)

Abstract

Crystal Structure and Superconductivity at about 30 K in $A$ Ca $_{2}$ Fe $_{4}$ As $_{4}$ F $_{2}$ ( $A$ = Rb, Cs)