Synthesis, crystal structure and superconductivity in Rb$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Sm, Tb, Dy and Ho)

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

doi:10.1021/acs.chemmater.6b05458

paper

Synthesis, crystal structure and superconductivity in Rb $L n_{2}$ Fe $_{4}$ As $_{4}$ O $_{2}$ ( $L n$ = Sm, Tb, Dy and Ho)

arXiv:1704.01075 · doi:10.1021/acs.chemmater.6b05458

Abstract

We have synthesized four iron-based oxyarsenide superconductors Rb $L n_{2}$ Fe $_{4}$ As $_{4}$ O $_{2}$ ( $L n$ = Sm, Tb, Dy and Ho) resulting from the intergrowth of RbFe $_{2}$ As $_{2}$ and $L n$ FeAsO. It is found that the lattice match between RbFe $_{2}$ As $_{2}$ and $L n$ FeAsO is crucial for the phase formation. The structural intergrowth leads to double asymmetric Fe $_{2}$ As $_{2}$ layers that are separated by insulating $L n_{2}$ O $_{2}$ slabs. Consequently, the materials are intrinsically doped at a level of 0.25 holes/Fe-atom and, bulk superconductivity emerges at $T_{c}$ = 35.8, 34.7, 34.3 and 33.8 K, respectively, for $L n$ = Sm, Tb, Dy and Ho. Investigation on the correlation between crystal structure and $T_{c}$ suggests that interlayer couplings may play an additional role for optimization of superconductivity.

20 pages, 9 figures, 1 table

Synthesis, crystal structure and superconductivity in RbLn2​Fe4​As4​O2​ (Ln = Sm, Tb, Dy and Ho)

Abstract

Synthesis, crystal structure and superconductivity in Rb $L n_{2}$ Fe $_{4}$ As $_{4}$ O $_{2}$ ( $L n$ = Sm, Tb, Dy and Ho)