Atomically imaged crystal structure and normal-state properties of superconducting Ca10Pt4As8

Abstract

Superconducting Ca 10 Pt 4 As 8 ((Fe 2 As 2) 5 is rare because optimal superconducting transition temperature is achieved without chemical doping or pressure. However, 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 P2 1 /n) with lattice parameters a = b = 8.76 Å, c = 20.18 Å, and γ =90.5º. Compared with previously reported structures derived from diffraction experiments, the c lattice constant is doubled due to alternating stacking of Pt 4 As 8 layers, which induces a high density of stacking faults. With the establishment of the crystal structure, stacking faults, and chemical composition, the distinctive normalstate electrical and thermal transport properties of our superconducting Ca 10 Pt 4 As 8 ((Fe 1-x Pt x) 2 As 2) 5 (x ~ 0.05) single crystals can be explained.

Mn-induced spin glass behavior in metallic Ir3Sn7−x Mn x

“…Here, ρ 0 is the residual resistivity, and AT 1/2 was proposed for a disordered system [25,26]. Similar T 1/2 dependence of the electrical resistivity was also observed in the normal state of Ca 10 Pt 4 As 8 (Fe 2 As 2 ) 5 superconductor [27]. Given that both compounds are metallic, and our resistivity measurement is on an Ir 3 Sn 7 single crystal (no doping), it is difficult to attribute the T 1/2 -term to disorder scattering.…”

In-plane p-wave coherence length in iron-based superconductors

“…Ni et al [57] discovered two iron arsenide superconductors, Ca10(Pt3As8)(Fe2As2)5 (the "10-3-8 phase" with Tc = 11 K) and Ca10(Pt4As8)(Fe2As2)5 (the "10-4-8 phase" with Tc = 26 K). Both phases have been extensively studied [58][59][60][61]. As this showed in recent experiments by 10-4-8 phase demonstrates very unusual pairing behaviour [62].…”