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

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.

19 pages, 10 figures

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Cited by in corpus (6)

• Spin-Triplet Superconductivity in K2Cr3As3
• Charge Density Wave order and electron-phonon coupling in ternary superconductor Bi${}_2$Rh${}_3$Se${}_2$
• Ultrafast Optical Spectroscopy Evidence of Pseudogap and Electron-Phonon Coupling in an Iron-Based Superconductor KCa${}_2$Fe${}_4$As${}_4$F${}_2$
• Elastoresistance measurements on CaKFe${}_4$As${}_4$ and KCa${}_2$Fe${}_4$As${}_4$F${}_2$ with the Fe site of $C_{2v}$ symmetry
• Anomalous metallic oxygen band in the potential superconductor KCa${}_2$Fe${}_4$As${}_4$O${}_2$
• Interplay of electron-phonon coupling, pseudogap, and superconductivity in CsCa${}_2$Fe${}_4$As${}_4$F${}_2$ studied using ultrafast optical spectroscopy