Atomically imaged crystal structure and normal-state properties of superconducting C a 10 P t 4 A s 8(( F e 1–x P t x)2 A s 2)5

• Published in: Physical review. B 2019-09, Vol.100 (9)
• Main Authors: Wang, Zhen, Jin, R., Wu, Lijun, Tao, Jing, Karki, A. B., Pan, J. Y., Zhu, Yimei, Plummer, E. W.
• Format: Article
• Language: English
• Subjects: CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.100.094103

Superconducting Ca10Pt4As8(Fe2As2)5 is rare because optimal superconducting transition temperature is achieved without chemical doping or pressure. Furthermore, the unclear crystal structure limits our ability to understand the structure-property relationship. Using atomically resolved scanning transmission electron microscopy and electron diffraction, we directly determine the structure of this superconductor: it forms a monoclinic structure (space group P21/n) with lattice parameters a = b = 8.76Å, c = 20.18Å, and γ = 90.5°. Compared with previously reported structures derived from diffraction experiments, the c-lattice constant is doubled due to alternating stacking of Pt4As8 layers, which induces a high density of stacking faults. With the establishment of the crystal structure, stacking faults, and chemical composition, the distinctive normal-state electrical and thermal transport properties of our superconducting Ca10Pt4As8((Fe1–xPtx)2As2)5 (x ~ 0.05) single crystals can be explained.