NMR Evidence for Inhomogeneous Nematic Fluctuations in BaFe_{2}(As_{1-x}P_{x})_{2}

A P Dioguardi; T Kissikov; C H Lin; K R Shirer; M M Lawson; H-J Grafe; J-H Chu; I R Fisher; R M Fernandes; N J Curro

doi:10.1103/PhysRevLett.116.107202

NMR Evidence for Inhomogeneous Nematic Fluctuations in BaFe_{2}(As_{1-x}P_{x})_{2}

Phys Rev Lett. 2016 Mar 11;116(10):107202. doi: 10.1103/PhysRevLett.116.107202. Epub 2016 Mar 10.

Authors

A P Dioguardi¹, T Kissikov¹, C H Lin¹, K R Shirer¹, M M Lawson¹, H-J Grafe², J-H Chu^{3

4}, I R Fisher^{3

4}, R M Fernandes⁵, N J Curro¹

Affiliations

¹ Department of Physics, University of California, Davis, California 95616, USA.
² IFW Dresden, Institute for Solid State Research, P.O. Box 270116, D-01171 Dresden, Germany.
³ Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
⁴ Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
⁵ School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.

PMID: 27015507
DOI: 10.1103/PhysRevLett.116.107202

Abstract

We present evidence for nuclear spin-lattice relaxation driven by glassy nematic fluctuations in isovalent P-doped BaFe_{2}As_{2} single crystals. Both the ^{75}As and ^{31}P sites exhibit a stretched-exponential relaxation similar to the electron-doped systems. By comparing the hyperfine fields and the relaxation rates at these sites we find that the As relaxation cannot be explained solely in terms of magnetic spin fluctuations. We demonstrate that nematic fluctuations couple to the As nuclear quadrupolar moment and can explain the excess relaxation. These results suggest that glassy nematic dynamics are a common phenomenon in the iron-based superconductors.