Spin dynamics near a putative antiferromagnetic quantum critical point in Cu substituted BaFe${}_2$As${}_2$ and its relation to high-temperature superconductivity

Abstract

We present the results of elastic and inelastic neutron scattering measurements on non-superconducting Ba(Fe${}_{0.957}$Cu${}_{0.043}$)${}_2$As${}_2$, a composition close to a quantum critical point between AFM ordered and paramagnetic phases. By comparing these results with the spin fluctuations in the low Cu composition as well as the parent compound BaFe${}_2$As${}_2$ and superconducting Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$ compounds, we demonstrate that paramagnon-like spin fluctuations are evident in the antiferromagnetically ordered state of Ba(Fe${}_{0.957}$Cu${}_{0.043}$)${}_2$As${}_2$, which is distinct from the AFM-like spin fluctuations in the superconducting compounds. Our observations suggest that Cu substitution decouples the interaction between quasiparticles and the spin fluctuations. We also show that the spin-spin correlation length, $\xi (T)$, increases rapidly as the temperature is lowered and find $\omega /T$ scaling behavior, the hallmark of quantum criticality, at an antiferromagnetic quantum critical point.

10 pages, 7 figures

References in corpus (24)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Effects of Co substitution on thermodynamic and transport properties and anisotropic $H_{c2}$ in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ single crystals
• Iron-Based Superconductors: current status of materials and pairing mechanism
• A Sharp Peak of the Zero-Temperature Penetration Depth at Optimal Composition in BaFe2(As1-xPx)2
• Superconductivity induced by Ni doping in BaFe${}_2$As${}_2$
• Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2
• Nematic spin correlations in the tetragonal state of uniaxial strained BaFe2-xNixAs2
• A neutron scattering study of the interplay between structure and magnetism in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Low energy spin waves and magnetic interactions in SrFe${}_2$As${}_2$
• Itinerant magnetic excitations in antiferromagnetic CaFe2As2
• Anisotropic itinerant magnetism and spin fluctuations in BaFe2As2: A neutron scattering study
• Nature of magnetic excitations in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• High energy spin excitations in BaFe2As2
• Coexistence and competition of the short-range incommensurate antiferromagnetic order with superconductivity in BaFe2-xNixAs2
• Anisotropic three-dimensional magnetism in CaFe2As2
• Itinerant Spin Excitations in SrFe2As2 Measured by Inelastic Neutron Scattering
• Enhancement of $T_c$ by disorder in underdoped iron pnictides
• Structural and magnetic phase transitions near optimal superconductivity in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Short-range cluster spin glass near optimal superconductivity in BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Suppression of antiferromagnetic order and orthorhombic distortion in superconducting Ba(Fe0.961Rh0.039)2As2
• Temperature dependence of the paramagnetic spin excitations in BaFe${}_2$As${}_2$
• Crossover from spin-waves to diffusive spin excitations in underdoped Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$

Cited by in corpus (11)

• Linear in Temperature Resistivity and Associated Mysteries
• Quantum-Critical Fluctuations in 2D Metals: Strange Metals and Superconductivity in Antiferromagnets and in Cuprates
• Electron doping evolution of the magnetic excitations in NaFe${}_{1-x}$Co${}_x$As
• Local breaking of four-fold rotational symmetry by short-range magnetic order in heavily overdoped Ba(Fe${}_{1-x}$Cu${}_x$)${}_2$As${}_2$
• Doping effects of Cr on the physical properties of BaFe${}_{1.9-x}$Ni${}_{0.1}$Cr${}_x$As${}_2$
• A Local Quantum Phase Transition in YFe${}_2$Al${}_{10}$
• Quantum critical behavior in Ce(Fe${}_{0.76}$Ru${}_{0.24}$)${}_2$Ge${}_2$: the full story
• Structural and antiferromagnetic properties of Ba(Fe${}_{1-x-y}$Co${}_x$Rh${}_y$)${}_2$As${}_2$ compounds
• Quantum-critical resistivity of strange metals in a magnetic field
• Crystal growth and characterization of a hole-doped iron-based superconductor Ba(Fe${}_{0.875}$Ti${}_{0.125}$)${}_2$As${}_2$
• Three-dimensional spin susceptibility in Ba${}_{0.75}$K${}_{0.25}$Fe${}_2$As${}_2$: Out-of-plane modulation revealed by neutron spectroscopy and theoretical modeling