Weak magnetism and the Mott-state of vanadium in superconducting Sr2VO3FeAs

Abstract

We report neutron scattering data and DFT calculations of the stoichiometric iron-arsenide superconductor Sr2VO3FeAs. Rietveld refinements of neutron powder patterns confirm the ideal composition without oxygen deficiencies. Experiments with polarized neutrons prove weak magnetic ordering in the V-sublattice of Sr2VO3FeAs at ~ 45 K with a probable propagation vector q = (1/8,1/8,0). The ordered moment of ~ 0.1 muB is too small to remove the V-3d bands from the Fermi level by magnetic exchange splitting, and much smaller than predicted from a recent LDA+U study. By using DFT calculations with a GGA+EECE functional we recover the typical quasi-nested Fermi-surface even without magnetic moment. From this we suggest that the V-atoms are in a Mott-state where the electronic correlations are dominated by on-site Coulomb-repulsion which shifts the V-3d states away from the Fermi energy. Our results are consistent with photoemission data and clearly reveal that Sr2VO3FeAs is a typical iron-arsenide superconductor with quasi-nested hole- and electron-like Fermi surface sheets, and constitutes no new paradigm. We suggest that intrinsic electron-doping through V3+/V4+ mixed valence is responsible for the absence of SDW ordering.

5 pages, 5 figures

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Cited by in corpus (6)

• Correlation of Fe-based Superconductivity and Electron-Phonon Coupling in an FeAs/Oxide Heterostructure
• Switching Magnetism and Superconductivity with Spin-Polarized Current in Iron-Based Superconductor
• Magnetism and superconductivity in Sr${}_2$VFeAsO${}_3$ revealed by ${}^{75}$As- and ${}^{51}$V-NMR under elevated pressures
• Superconducting transition temperatures in the electronic and magnetic phase diagrams of Sr2VFeAsO3-delta, a superconductor
• Coupled Magnetic and Superconducting Transitions in Sr${}_2$VO${}_3$FeAs Under Pressure
• Role of Vanadium-Oxide Layer in Electronic State of Sr${}_2$VFeAsO${}_{3-\delta }$ with Oxygen Deficiency