Hidden spin liquid in an antiferromagnet: Applications to FeCrAs

Abstract

The recently studied material FeCrAs exhibits a surprising combination of experimental signatures, with metallic, Fermi liquid like specific heat but resistivity showing strong non-metallic character. The Cr sublattice posseses local magnetic moments, in the form of stacked (distorted) Kagome lattices. Despite the high degree of magnetic frustration, anti-ferromagnetic order develops below ~125K suggesting the non-magnetic Fe sublattice may play a role in stabilizing the ordering. From the material properties we propose a microscopic Hamiltonian for the low energy degrees of freedom, including the non-magnetic Fe sublattice, and study its properties using slave-rotor mean field theory. Using this approach we find a spin liquid phase on the Fe sublattice, which survives even in the presence of the magnetic Cr sublattice. Finally, we suggest that the features of FeCrAs can be qualitatively explained by critical fluctuations in the non-magnetic sublattice Fe due to proximity to a metal-insulator transition.

9 pages, 8 figures

References in corpus (8)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Quantum frustration in organic Mott insulators: from spin liquids to unconventional superconductors
• Frustration and the Kondo effect in heavy fermion materials
• Quantum criticality in the iron pnictides and chalcogenides
• Self-consistent slave rotor mean field theory for strongly correlated systems
• A novel non-Fermi-liquid state in the iron-pnictide FeCrAs
• Global Phase Diagram of the Kondo Lattice: From Heavy Fermion Metals to Kondo Insulators
• Emergence of superconductivity, valence bond order and Mott insulators in Pd[(dmit)2] based organic salts

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• Coexistence of metallic and nonmetallic properties in the pyrochlore Lu${}_2$Rh${}_2$O${}_7$
• Optical properties and electronic structure of the nonmetallic metal FeCrAs
• Local magnetism, magnetic order and spin freezing in the 'nonmetallic metal' FeCrAs
• From mean-field localized magnetism to itinerant spin fluctuations in the "Non-metallic metal" - FeCrAs
• Spin reorientation in FeCrAs revealed by single-crystal neutron diffraction
• Correlation stabilized ferromagnetic MnRuAs with distorted kagome lattice
• Fluctuating magnetism of Co- and Cu-doped NaFeAs
• Enhanced Neel temperature and unusual thermal expansion in flux-grown FeCrAs crystals
• Honeycomb lattice iridate on the verge of Mott-collapse