Coupling of structure to magnetic and superconducting orders in quasi-one-dimensional K 2 Cr 3 As 3

K. M. Taddei, Q. Zheng, A. S. Sefat, C. De La Cruz

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24 Scopus citations

Abstract

Quasi-one-dimensional A 2 Cr 3 As 3 (with A=K, Cs, Rb) is an intriguing new family of superconductors which exhibit many similar features to the cuprate and iron-based unconventional superconductor families. Yet, in contrast to these systems, no charge or magnetic ordering has been observed which could provide the electronic correlations presumed necessary for an unconventional superconducting pairing mechanism - an absence which defies predictions of first-principles models. We report the results of neutron scattering experiments on polycrystalline K 2 Cr 3 As 3 (Tc∼7K) which probed the lowerature dynamics near Tc. Neutron diffraction data evidence a subtle response of the nuclear lattice to the onset of superconductivity while inelastic scattering reveals a highly dispersive column of intensity at the commensurate wave vector q=0012 which loses intensity beneath Tc - indicative of short-range magnetic fluctuations. Using linear spin-wave theory, we model the observed scattering and suggest a possible structure to the short-range magnetic order. These observations suggest that K 2 Cr 3 As 3 is in close proximity to a magnetic instability and that the incipient magnetic order both couples strongly to the lattice and competes with superconductivity, in direct analogy with the iron-based superconductors.

Original languageEnglish
Article number180506
JournalPhysical Review B
Volume96
Issue number18
DOIs
StatePublished - Nov 20 2017

Funding

The part of the research that was conducted at ORNL's High Flux Isotope Reactor and Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The research is partly supported by the US Department of Energy(DOE), Office of Science, Basic Energy Sciences (BES), Materials Science and Engineering Division. The authors thank S. Chi for providing help during experimental collection and analysis. ORNL is managed by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The US Government retains and the publisher, by accepting the article for publication, acknowledges that the US Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US Government purposes.

FundersFunder number
Scientific User Facilities Division
U.S. Department of Energy
Office of Science
Basic Energy Sciences
Oak Ridge National LaboratoryDE-AC05-00OR22725
Division of Materials Sciences and Engineering
UT-Battelle

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