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An inelastic neutron scattering study of the spin waves corresponding to the stripe antiferromagnetic order in insulating Rb$_{0.8}$Fe$_{1.5}$S$_2$ throughout the Brillouin zone is reported. The spin wave spectra are well described by a Heisenberg Hamiltonian with anisotropic in-plane exchange interactions. Integrating the ordered moment and the spin fluctuations results in a total moment squared of $27.6pm4.2mu_B^2$/Fe, consistent with $mathrm{S approx 2}$. Unlike $X$Fe$_2$As$_2$ ($X=$ Ca, Sr, and Ba), where the itinerant electrons have a significant contribution, our data suggest that this stripe antiferromagnetically ordered phase in Rb$_{0.8}$Fe$_{1.5}$S$_2$ is a Mott-like insulator with fully localized $3d$ electrons and a high-spin ground state configuration. Nevertheless, the anisotropic exchange couplings appear to be universal in the stripe phase of Fe pnictides and chalcogenides.
A combination of neutron diffraction and angle-resolved photoemission spectroscopy measurements on a pure antiferromagnetic stripe Rb$_{1-delta}$Fe$_{1.5-sigma}$S$_2$ is reported. A neutron diffraction experiment on a powder sample shows that a 98$%$
We show that electronic Raman scattering affords a window into the essential properties of the pairing potential $V_{mathbf{k},mathbf{k^{prime}}}$ of iron-based superconductors. In Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ we observe band dependent energy gaps
Magnetism of the $S$ = 1 Heisenberg antiferromagnets on the spatially anisotropic square lattice has been scarcely explored. Here we report a study of the magnetism, specific heat, and thermal conductivity on Ni[SC(NH$_2$)$_2$]$_6$Br$_2$ (DHN) single
Inelastic neutron scattering measurements have been performed to investigate the spin waves of the quasi-one-dimensional antiferromagnetic ladder compound BaFe$_2$S$_3$, where a superconducting transition was observed under pressure [H. Takahashi {it
The spatially averaged density of states, <N(0)>, of an unconventional d-wave superconductor is magnetic field dependent, proportional to $H^{1/2}$, owing to the Doppler shift of quasiparticle excitations in a background of vortex supercurrents[1,2].