Strong local moment antiferromagnetic spin fluctuations in V-doped LiFeAs

Abstract

We use neutron scattering to study vanadium (hole)-doped LiFe${}_{1-x}$V${}_x$As. In the undoped state, LiFeAs exhibits superconductivity at $T_c=18$ K and transverse incommensurate spin excitations similar to electron overdoped iron pnictides. Upon vanadium-doping to form LiFe${}_{0.955}$V${}_{0.045}$, the transverse incommensurate spin excitations in LiFeAs transform into longitudinally elongated in a similar fashion as that of potassium (hole) doped Ba${}_{0.7}$K${}_{0.3}$Fe${}_2$As${}_2$, but with dramatically enhanced magnetic scattering and elimination of superconductivity. This is different from the suppression of the overall magnetic excitations in hole doped BaFe${}_2$As${}_2$ and the enhancement of superconductivity near optimal hole doping. These results are consistent with density function theory plus dynamic mean field theory calculations, suggesting that vanadium-doping in LiFeAs may induce an enlarged effective magnetic moment $S_{eff}$ with a spin crossover ground state arising from the inter-orbital scattering of itinerant electrons.

Accepted by npj Quantum Materials

References in corpus (22)

• Strong electronic correlations from Hund's coupling
• Quantum Monte Carlo Impurity Solver for Cluster DMFT and Electronic Structure Calculations in Adjustable Base
• Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors
• Magnetism and Charge Dynamics in Iron Pnictides
• Nature of magnetic excitations in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Spin-state transition in the Fe-pnictides
• Competition between stripe and checkerboard magnetic instabilities in Mn-doped BaFe2As2
• Electron doping evolution of the anisotropic spin excitations in BaFe2-xNixAs2
• Orbital-selective Mott phase in multiorbital models for iron pnictides and chalcogenides
• Enhancing magnetic stripe order in iron pnictides by RKKY exchange interactions
• Orbital-differentiated coherence-incoherence crossover identified by photoemission spectroscopy in LiFeAs
• Detailed band structure of twinned and detwinned BaFe${}_2$As${}_2$ studied with angle-resolved photoemission spectroscopy
• Effect of Li-deficiency impurities on the electron-overdoped LiFeAs superconductor
• Antiferromagnetic spin excitations in single crystals of nonsuperconducting Li1-xFeAs
• The magnetic moment enigma in Fe-based high temperature superconductors
• Spectral analysis for the iron-based superconductors: Anisotropic spin fluctuations and fully gapped s^{\pm}-wave superconductivity
• Incommensurate antiferromagnetic fluctuations in single-crystalline LiFeAs studied by inelastic neutron scattering
• The anomaly Cu doping effects on LiFeAs superconductors
• Analytical slave-spin mean-field approach to orbital selective Mott insulators
• NaFe${}_{0.56}$Cu${}_{0.44}$As: A pnictide insulating phase induced by on-site Coulomb interaction
• Spin fluctuation anisotropy as a probe of orbital-selective hole-electron quasiparticle excitations in detwinned Ba(Fe1-xCox)2As2
• Observation of an Emergent Coherent State in the Iron-Based Superconductor KFe${}_2$As${}_2$