Abstract
The relationship between charge-density wave (CDW) orders and superconductivity in arsenide superconductor with which crystallizes in the -type structure was studied by nuclear magnetic resonance (NMR) measurements up to 520 K, and nuclear quadrupole resonance (NQR) and measurements down to 1.5 K. At high temperature, spectrum and nuclear-spin-relaxation rate have revealed two distinct CDW orders, one realized in the As-Pt-As layer below and the other in the Pt-As-Pt layer below . The measured by shows a clear Hebel-Slichter peak just below and decreases exponentially well below . Concomitantly, Knight shift decreases below . Our results indicate that superconductivity in is in the spin-singlet state with an -wave gap and is robust under the two distinct CDW orders in different layers.
- Received 6 January 2015
- Revised 30 January 2015
DOI:https://doi.org/10.1103/PhysRevB.91.060510
©2015 American Physical Society