Related papers: Unified Spin Model for Magnetic Excitations in Iro…
We have used inelastic neutron scattering and muon-spin rotation to compare the low energy magnetic excitations in single crystals of superconducting Fe1.01Se0.50Te0.50 and non-superconducting Fe1.10Se0.25Te0.75. We confirm the existence of…
Resolving the interplay between magnetic interactions and structural properties in strongly correlated materials through a quantitatively accurate approach has been a major challenge in condensed matter physics. Here we apply highly…
Iron telluride FeTe is known to display bicollinear magnetic order at low temperatures together with a monoclinic lattice distortion. Because the bicollinear order can involve two different wavevectors $(\pi/2,\pi/2)$ and $(\pi/2,-\pi/2)$,…
The Fe1+xTe phase diagram consists of two distinct magnetic structures with collinear order present at low interstitial iron concentrations and a helical phase at large values of x with these phases separated by a Lifshitz point. We use…
Recent neutron scattering experiments addressing the magnetic state of the two-leg ladder selenide compound BaFe$_2$Se$_3$ have unveiled a dominant spin arrangement involving ferromagnetically ordered 2$\times$2 iron-superblocks, that are…
We report on inelastic neutron scattering measurements that find incommensurate itinerant like magnetic excitations in the normal state of superconducting FeTe$_{0.6}$Se$_{0.4}$ (\Tc=14K) at wave-vector…
Unconventional superconductivity typically emerges in the presence of quasi-degenerate ground states, and the associated intense fluctuations are likely responsible for generating the superconducting state. Here we use polarized neutron…
Magnetic and ferroelectric properties of layered geometrically frustrated cluster compound FeTe$_2$O$_5$Br were investigated with single-crystal neutron diffraction and dielectric measurements. Incommensurate amplitude modulated magnetic…
We analyze magnetic order in iron-chalcogenide Fe$_{1+y}$Te -- the parent compound of high-temperature superconductor Fe$_{1+y}$Te$_{1-x}$Se$_x$. Neutron scattering experiments show that magnetic order in this material contains components…
Spin nematic order is investigated for a S=1 spin model on triangular lattice with bilinear-biquadratic interactions. We particularly studied an antiferro nematic order phase with three-sublattice structure, and magnetic properties are…
The charge and spin dynamics of the structurally simplest iron-based superconductor, FeSe, may hold the key to understanding the physics of high temperature superconductors in general. Unlike the iron pnictides, FeSe lacks long range…
Motivated by recent experimental and theoretical progresses of the magnetic properties of iron-based superconductors, we provide a comprehensive analysis of the spin-1 bilinear-biquadratic (BBQ) model on the square lattice. Using…
Quasi-one-dimensional iron chalcogenides possess various magnetic states depending on the lattice distortion, electronic correlations, and presence of defects. We present neutron diffraction and inelastic neutron scattering experiments on…
To elucidate the magnetic structure and the origin of the nematicity in FeSe, we perform a high-pressure $^{77}$Se NMR study on FeSe single crystals. We find a suppression of the structural transition temperature with pressure up to about 2…
A hallmark of the iron-based superconductors is the strong coupling between magnetic, structural and electronic degrees of freedom. However, a universal picture of the normal state properties of these compounds has been confounded by recent…
Intertwined spin and charge orders have been widely studied in high-temperature superconductors, since their fluctuations may facilitate electron pairing; however, they are rarely identified in heavily electron-doped iron selenides. Here,…
The iron-based superconductor FeSe isovalently substituted with S displays an abundance of remarkable phenomena that have not been fully understood, at the center of which are apparent zero-energy excitations in the superconducting state in…
The magnetic properties of iron-arsenides are investigated using the LSDA+U approach. In addition to one high moment state, we find that a positive U also produces two low moment states with m~0.4 $\mu_{B}$ and m~1.0 $\mu_{B}$. The…
Polarized Raman-scattering spectra of superconducting, single-crystalline FeSe evidence pronounced phonon anomalies with temperature reduction. A large 6.5% hardening of the B_1g(Fe) phonon mode is attributed to the suppression of local…
The pressure effects on the antiferromagentic orders in iron-based ladder compounds CsFe$_2$Se$_3$ and BaFe$_2$S$_3$ have been studied using neutron diffraction. With identical crystal structure and similar magnetic structures, the two…