Nodeless energy gaps of single-crystalline Ba0.68K 0.32Fe2As2 as seen via As75 NMR

Z. Li, D. L. Sun, C. T. Lin, Y. H. Su, J. P. Hu, Guo-Qing Zheng

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

We report As75 nuclear magnetic resonance studies on a very clean hole-doped single-crystal Ba0.68K0.32Fe2As 2 (Tc=38.5 K). The spin-lattice relaxation rate 1/T 1 shows an exponential decrease below T0.45Tc down to T0.11Tc, which indicates a fully opened energy gap. From the ratio (T1)c/(T1)a, where a and c denote the crystal directions, we find that the antiferromagnetic spin fluctuation is anisotropic in the spin space above Tc. The anisotropy decreases below Tc and disappears at T→0. We argue that the anisotropy stems from spin-orbit coupling whose effect vanishes when spin-singlet electron pairs form with a nodeless gap.

Original languageEnglish
Article number140506
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume83
Issue number14
DOIs
Publication statusPublished - Apr 18 2011

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Energy gap
Anisotropy
Nuclear magnetic resonance
Crystalline materials
Spin fluctuations
nuclear magnetic resonance
Spin-lattice relaxation
anisotropy
Orbits
Single crystals
stems
doped crystals
spin-lattice relaxation
electron spin
Crystals
Electrons
orbits
single crystals
crystals
Direction compound

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Nodeless energy gaps of single-crystalline Ba0.68K 0.32Fe2As2 as seen via As75 NMR. / Li, Z.; Sun, D. L.; Lin, C. T.; Su, Y. H.; Hu, J. P.; Zheng, Guo-Qing.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 83, No. 14, 140506, 18.04.2011.

Research output: Contribution to journalArticle

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