Nematicity in LaFeAsO1−xFx

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • C. Hess - , Leibniz Institute for Solid State and Materials Research Dresden, TUD Dresden University of Technology (Author)
  • H. Grafe - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • A. Kondrat - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • G. Lang - , Leibniz Institute for Solid State and Materials Research Dresden, Sorbonne Université (Author)
  • F. Hammerath - , Chair of Solid State Physics/Electronic Properties, Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • L. Wang - , Leibniz Institute for Solid State and Materials Research Dresden, Karlsruhe Institute of Technology (Author)
  • R. Klingeler - , Heidelberg University  (Author)
  • G. Behr - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • B. Büchner - , Center for Transport and Devices of Emergent Materials (CTD), Chair of Experimental Solid State Physics, Leibniz Institute for Solid State and Materials Research Dresden (Author)

Abstract

Orbital ordering has recently emerged as another important state in iron-based superconductors, and its role for superconductivity as well as its connection to magnetic order and orthorhombic lattice distortion are heavily debated. In order to search for signatures of this so-called nematic phase in oxypnictides, we revisit the normal state properties of the pnictide superconductor LaFeAsO1−x Fx with a focus on resistivity, Nernst effect, thermal expansion, and 75 As nuclear magnetic resonance (NMR) data. The transport properties at the underdoped level x = 0.05 exhibit pronounced anomalies at about the same temperature where undoped LaFeAsO develops long-range nematic ordering, i.e., at about 160 K. Furthermore, the 75 As-NMR spin-lattice relaxation rate (T1T)-1 reveals a progressive slowing down of spin fluctuations. Yet, long-range magnetic order and also a detectable orthorhombic lattice distortion are absent. Thus, we conclude from the data that short-range orbital-nematic ordering or a slowly fluctuating form of it sets in near 160 K. Remarkably, all anomalies in the transport and also the indications of slow spin fluctuations disappear close to optimal doping x = 0.01 which suggests that in LaFeAsO1−x Fx the nematic phase actually competes with superconductivity. Schematic electronic phase diagram of LaFeAsO1−x Fx.

Details

Original languageEnglish
Article number1600214
JournalPhysica Status Solidi (B) Basic Research
Volume254
Issue number1
Publication statusPublished - 1 Jan 2017
Peer-reviewedYes

Keywords

Keywords

  • iron pnictide superconductors, Magnetic resonance, nematic order, transport