Evidence for a full energy gap for nickel-pnictide LaNiAsO {1-x}F x superconductors by ^{75}As nuclear quadrupole resonance - Condensed Matter > SuperconductivityReport as inadecuate




Evidence for a full energy gap for nickel-pnictide LaNiAsO {1-x}F x superconductors by ^{75}As nuclear quadrupole resonance - Condensed Matter > Superconductivity - Download this document for free, or read online. Document in PDF available to download.

Abstract: We report systematic ^{75}As-NQR and ^{139}La-NMR studies on nickel-pnictidesuperconductors LaNiAsO {1-x}F x x=0, 0.06, 0.10 and 0.12. The spin latticerelaxation rate 1-T 1 decreases below T c with a well-defined coherence peakand follows an exponential decay at low temperatures. This result indicatesthat the superconducting gap is fully opened, and is strikingly different fromthat observed in iron-pnictide analogs. In the normal state, 1-T 1T is constantin the temperature range T c \sim 4 K < T <10 K for all compounds and up toT=250 K for x=0 and 0.06, which indicates weak electron correlations and isalso different from the iron analog. We argue that the differences between theiron and nickel pnictides arise from the different electronic band structure.Our results highlight the importance of the peculiar Fermi-surface topology iniron-pnictides.



Author: T. Tabuchi, Z. Li, G.F. Chen, S. Kawasaki, J.L. Luo, N.L. Wang, Guo-qing Zheng

Source: https://arxiv.org/



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