Unconventional Multi-gap Superconductivity and Antiferromagnetic Spin Fluctuations in New Iron-arsenide LaFe2As2 in Heavily Electron-doped Regime

We report 75As-NMR/NQR results on new iron-arsenide compounds (La0.5−xNa0.5+x)Fe2As2. The parent compound x = 0 exhibits a stripe-type antiferromagnetic (AFM) order below TN = 130 K. The measuremen...