Related papers: Spin density wave and superconductivity in CaFe_{1…
We report muon spin rotation (muSR) and infrared (IR) spectroscopy experiments on underdoped BaFe1.89Co0.11As2 which show that bulk magnetism and superconductivity (SC) coexist and compete on the nanometer length scale. Our combined data…
The spin dynamics in single crystal, electron-doped Ba(Fe1-xCox)2As2 has been investigated by inelastic neutron scattering over the full range from undoped to the overdoped regime. We observe damped magnetic fluctuations in the normal state…
We systematically investigate the photoexcited (PE) quasi-particle (QP) relaxation and low-energy electronic structure in electron doped Ba(Fe_{1-x}Co_{x})_{2}As_{2} single crystals as a function of Co doping, 0<= x <=0.11. The evolution of…
The coexisting regime of spin density wave (SDW) and superconductivity in the iron pnictides represents a novel ground state. We have performed high resolution angle-resolved photoemission measurements on NaFe1-xCoxAs (x = 0.0175) in this…
We report synthesis, structural details and magnetization of SmFe1-xCoxAsO with x ranging from 0.0 to 1.0 at close interval of 0.10. It is found that Co substitutes fully at Fe site in SmFeAsO in an iso-structural lattice with slightly…
In iron-based superconductors, a spin-density-wave (SDW) magnetic order is suppressed with doping and unconventional superconductivity appears in close proximity to the SDW instability. The optical response of the SDW order shows clear gap…
We study the interplay of fluctuations and superconductivity in BaFe$_2$As$_2$ (Ba-122) compounds with Ba and Fe substituted by K ($p$ doping) and Co ($n$ doping), respectively. To this end we measured electronic Raman spectra as a function…
We report Eu-local-spin magnetism and Ni-doping-induced superconductivity (SC) in a 112-type ferroarsenide system Eu(Fe$_{1-x}$Ni$_{x}$)As$_2$. The non-doped EuFeAs$_2$ exhibits two primary magnetic transitions at $\sim$100 and $\sim$ 40 K,…
The evolution of low-energy spin dynamics in the iron-based superconductor LaFeAsO$_{1-x}$F$_x$ was studied over a broad doping, temperature, and magnetic field range (x = 0 - 0.15, T up to 480K, H up to 30T) by means of As nuclear magnetic…
We present nuclear magnetic resonance evidence that very slow ($\leq 1$ MHz) spin fluctuations persist into the overdoped regime of Ba(Fe$_{1-x}$Rh$_{x}$)$_2$As$_2$ superconductors. Measurements of the $^{75}$As spin echo decay rate,…
We use density functional theory to investigate effects of spin-orbit coupling and single-stripe-type antiferromagnetic (sAFM) ordering on the crystal structure and electronic properties of SmFeAsO. The results indicate that AFM ordering…
We report 75As-nuclear quadrupole resonance (NQR) studies on (Ca_4Al_2O_{6-y})(Fe_2As_2) with Tc=27K, which unravel unique normal-state properties and point to unconventional nodeless superconductivity (SC). Measurement of…
Low energy spin fluctuations are studied for the electron-doped Fe-based superconductor LaFeAsO(1-x)F(x) by inelastic neutron scattering up to the energy transfer of w = 15 meV using polycrystalline samples. Superconducting samples…
We use elastic and inelastic neutron scattering to systematically investigate the evolution of the low-energy spin excitations of the iron arsenide superconductor BaFe2-xNixAs2 as a function of nickel doping x. In the undoped state,…
Using first-principles calculation methods, we reveal a series of phase transitions as a function of electron doping in single-layer 1T$'$-MoTe$_2$ and 1T$'$-WTe$_2$ exhibiting quantum spin Hall (QSH) edge states without doping. As…
We study a unified mechanism for spin-density-wave (SDW) and superconductivity in a minimal model, in which itinerant electrons and local moments coexist as previously proposed for the iron pnictides [EPL, 88, 17010 (2009)]. The phase…
A series of $1T$-Fe$_x$Ta$_{1-x}$SSe (0 $\leq x \leq$ 0.1) single crystals was fabricated via the chemical-vapor-transport (CVT) method and investigated by structure, transport, and magnetic measurements along with the…
We study the properties of a spin-density-wave antiferromagnetic mean-field ground state with d-wave superconducting (DSC) correlations. This ground state always gains energy by Cooper pairing. It would fail to superconduct at half-filling…
We study the interplay between superconductivity and antiferromagnetic spin fluctuations in electron-doped cobaltate Na$_{x}$CoO$_{2}\cdot y$H$_{2}$O based on the kinetic energy driven superconductivity mechanism. We show that the…
We report the Ni-doping effect on magnetism and superconductivity (SC) in an Eu-containing 112-type system Eu(Fe$_{1-x}$Ni$_{x})$As$_{2}$ ($0\leq x\leq 0.15$) by the measurements of resistivity, magnetization, and specific heat. The undoped…