Giant anisotropy in superconducting single crystals of CsCa2Fe4As4F2
Abstract
CsCa2Fe4As4F2 is a newly discovered iron-based superconductor with Tc 30 K containing double Fe2As2 layers that are separated by insulating Ca2F2 spacer layers. Here we report the transport and magnetization measurements on CsCa2Fe4As4F2 single crystals grown for the first time using the self flux of CsAs. We observed a huge resistivity anisotropy c(T)/ab(T), which increases with decreasing temperature, from 750 at 300 K to 3150 at 32 K. The c(T) data exhibit a non-metallic behavior above 140 K, suggesting an incoherent electronic state at high temperatures due to the dimension crossover. The superconducting onset transition temperature in ab is 0.7 K higher than that in c, suggesting two-dimensional (2D) superconducting fluctuations. The lower and upper critical fields also show an exceptional anisotropy among iron-based superconductors. The Hc1(T) data are well fitted using the model with two s-wave-like superconducting gaps, 1(0)=6.75 meV and 2(0)=2.32 meV. The inter-plane coherence length c(0) is 3.6 , remarkably smaller than the distance between conducting layers (8.6 ), consolidating the 2D nature in the title material.
Turn this paper into a lesson
ArcXiv compiles a structured reading guide from this paper's metadata: plain-English importance, contributions, prerequisite concepts, which sections to read first, flashcards, and a quiz. Grounded in the abstract, never invented.