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Coexistence of Ferromagnetic and Stripe Antiferromagnetic Spin Fluctuations in SrCo2 As2

Journal Article · · Physical Review Letters
 [1];  [2];  [3];  [4];  [2];  [4];  [2];  [3];  [3];  [5];  [5];  [6];  [6];  [5];  [5];  [7];  [8];  [9];  [1]
  1. Rice Univ., Houston, TX (United States); Beijing Normal Univ. (China)
  2. Beijing Normal Univ. (China)
  3. Chinese Academy of Sciences (CAS), Shanghai (China)
  4. Rice Univ., Houston, TX (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab., ISIS Neutron Source
  7. Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France)
  8. Inst. Laue-Langevin (ILL), Grenoble (France)
  9. Julich Research Centre (Germany). Julich Centre for Neutron Science (JCNS)
We use inelastic neutron scattering to study energy and wave vector dependence of spin fluctuations in SrCo2As2, derived from SrFe2-xCoxAs2 iron pnictide superconductors. Our data reveal the coexistence of antiferromagnetic (AF) and ferromagnetic (FM) spin fluctuations at wave vectors QAF=(1,0) and QFM=(0,0)/(2,0), respectively. By comparing neutron scattering results with those of dynamic mean field theory calculation and angle-resolved photoemission spectroscopy experiments, we conclude that both AF and FM spin fluctuations in SrCo2As2 are closely associated with a flatband of the eg orbitals near the Fermi level, different from the t2g orbitals in superconducting SrFe2-xCoxAs2. Therefore, Co substitution in SrFe2-xCoxAs2 induces a t2g to eg orbital switching, and is responsible for FM spin fluctuations detrimental to the singlet pairing superconductivity.
Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1509529
Journal Information:
Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 11 Vol. 122; ISSN 0031-9007; ISSN PRLTAO
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English

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Cited By (4)

Suppression of ferromagnetic spin fluctuations in the filled skutterudite superconductor SrOs 4 As 12 revealed by As 75 NMR-NQR measurements journal August 2019
Flat-band magnetism and helical magnetic order in Ni-doped SrCo 2 As 2 journal September 2019
Non-Fermi-liquid types of behavior associated with a magnetic quantum critical point in Sr ( Co 1 − x Ni x ) 2 As 2 single crystals journal September 2019
Helical magnetic ordering in Sr ( Co 1 − x Ni x ) 2 As 2 journal October 2019

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