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arXiv · 2005.05029

NMR and NQR studies on transition-metal arsenide superconductors LaRu2As2, KCa2Fe4As4F2, and A2Cr3As3

Jun Luo·Chunguang Wang·Zhicheng Wang·Qi Guo·Jie Yang·Rui Zhou·K. Matano·T. Oguchi·Zhian Ren·Guanghan Cao·Guo-qing Zheng
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Abstract

We report 75As-nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on transition-metal arsenides LaRu2As2, KCa2Fe4As4F2, and A2Cr3As3. In the superconducting state of LaRu2As2, a Hebel- Slichter coherence peak is found in the temperature dependence of the spin-lattice relaxation rate-1/T1 just below Tc, which indicates that LaRu2As2 is a full-gap superperconducor. For KCa2Fe4As4F2, antiferromagnetic spin fluctuations are observed in the normal state. We further find that the anisotropy rate RAF = Tc1/Tab1 is small and temperature independent, implying that the low energy spin fluctuations are isotropic in spin space. Our results indicate that KCa2Fe4As4F2 is a moderately overdoped iron-arsenide high-temperature superconductor with a stoichiometric composition. For A2Cr3As3, we calculate the electric field gradient by first-principle method and assign the 75As-NQR peaks with two crystallographically different As sites, paving the way for further NMR investigation.

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Jun Luo, Chunguang Wang, Zhicheng Wang, Qi Guo, Jie Yang, Rui Zhou, K. Matano, T. Oguchi, Zhian Ren, Guanghan Cao, Guo-qing Zheng. 2020-05-11. NMR and NQR studies on transition-metal arsenide superconductors LaRu2As2, KCa2Fe4As4F2, and A2Cr3As3. https://doi.org/10.1088/1674-1056/ab892d

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