相关论文: Linkage between scattering rates and superconducti…
Electronic Raman scattering from high- and low-energy excitations was studied as a function of temperature, extent of hole doping, and energy of the incident photons in Bi_2Sr_2CaCu_2O_{8 \pm \delta} superconductors. For underdoped…
For YBa_2Cu_3O_{6+\delta} and Bi_2Sr_2CaCu_2O_8 superconductors, electronic Raman scattering from high- and low-energy excitations has been studied in relation to the hole doping level, temperature, and energy of the incident photons. For…
Using polarization-resolved electronic Raman scattering we study under-doped, optimally-doped and over-doped Ba$_{1-x}$K$_{x}$Fe$_2$As$_2$ samples in the normal and superconducting states. We show that low-energy nematic fluctuations are…
Angle-resolved photoemission spectroscopy (ARPES) is used to study the scattering rates of charge carriers from the hole pockets near Gamma in the iron-based high-Tc hole doped superconductors KxBa1-xFe2As2 x=0.4 and KxEu1-xFe2As2 x=0.55$…
Inelastic scattering of visible light (Raman effect) offers a window into properties of correlated metals such as spin, electron and lattice dynamics as well as their mutual interactions. In this review we focus on electronic and spin…
The spin dynamics in single crystal, electron-doped Ba(Fe1-xCox)2As2 has been investigated by inelastic neutron scattering over the full range from undoped to the overdoped regime. We observe damped magnetic fluctuations in the normal state…
A series of layered (Sr$_{1-x}$K$_x$)Fe$_2$As$_2$ compounds with nominal x=0 to 0.40 are synthesized by solid state reaction method. Similar to other parent compounds of iron-based pnictide superconductors, the pure SrFe$_2$As$_2$ shows a…
Superconductivity originates from pairing of electrons. Pairing channel on Fermi surface and pairing glue are thus two pivotal issues for understanding a superconductor. Recently, high-temperature superconductivity over 40 K was found in…
We report optical spectroscopic measurements on electron- and hole-doped BaFe2As2. We show that the compounds in the normal state are not simple metals. The optical conductivity spectra contain, in addition to the free carrier response at…
We report inelastic neutron scattering experiments on single crystals of superconducting Ba0.67K0.33Fe2As2 (Tc = 38 K). In addition to confirming the resonance previously found in powder samples, we find that spin excitations in the normal…
We investigate the superconducting phase in the K(x)Ba(1-x)Fe2As2 122 compounds from moderate to strong hole-doping regimes. Using functional renormalization group, we show that while the system develops a nodeless anisotropic s+- order…
BaFe2As2 is the parent compound of the '122' iron arsenide superconductors and crystallizes with the tetragonal ThCr2Si2 type structure, space group I4/mmm. A spin density wave transition at 140 K is accompanied by a symmetry reduction to…
To gain insight into the unconventional superconductivity of Fe-pnictides with no electron pockets, we measure the thermal conductivity $\kappa$ and penetration depth $\lambda$ in the heavily hole-doped regime of…
We investigated four single crystals of K-doped BaFe$_2$As$_2$ (Ba-122), Ba$_{1-x}$K$_x$Fe$_2$As$_2$ with $x$ = 0.29, 0.36, 0.40, and 0.51, using infrared spectroscopy. We explored a wide variety of doping levels, from under- to overdoped.…
The phase diagram of the cuprate superconductors continues to pose formidable scientific challenges. While these materials are typically viewed as doped Mott insulators, it is well known that they are Fermi liquids at high hole-dopant…
High-temperature superconductivity in iron pnictides occurs when electrons are doped into their antiferromagnetic (AF) parent compounds. In addition to inducing superconductivity, electron-doping also changes the static commensurate AF…
The superconductivity in high temperature superconductors ordinarily arises when doped with hetero-valent ions that introduce charge carriers. However, in ferropnictides, "iso-valent" doping, which is generally believed not to introduce…
We have investigated the superconducting gap of optimally doped Ba(Fe$_{0.65}$Ru$_{0.35}$)$_2$As$_2$ by angle-resolved photoemission spectroscopy (APRES) using bulk-sensitive 7 eV laser and synchrotron radiation. It was found that the gap…
A neutron scattering study of heavily hole-overdoped superconducting KFe$_2$As$_2$ revealed a well-defined low-energy incommensurate spin fluctuation at [$\pi(1\pm2\delta$),0] with $\delta$ = 0.16. The incommensurate structure differs from…
High temperature superconductivity in cuprates is realized by doping the Mott insulator with charge carriers. A central issue is how such an insulating state can evolve into a conducting or superconducting state when charge carriers are…