Related papers: Interstitial Iron Controlled Superconductivity in …
A very fundamental and unconventional characteristic of superconductivity in iron-based materials is that it occurs in the vicinity of {\it two} other instabilities. Apart from a tendency towards magnetic order, these Fe-based systems have…
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…
We demonstrate that the differential conductance, $dI/dV$, measured via spectroscopic imaging scanning tunneling microscopy in the doped iron chalcogenide FeSe$_{0.45}$Te$_{0.55}$, possesses a series of characteristic features that allow…
The crystal structure of the superconductor FeSe0.44Te0.56 was redetermined by high-resolution X-ray single crystal diffraction at 173 K (anti-PbO-type, P4/nmm, a=3.7996(2), c=5.9895(6) A, R1=0.022, wR2=0.041, 173 F^2). Significantly…
The atomically clean surface of the iron-based superconductor FeTe0.55Se0.45 is investigated by low-temperature STM with different tip apex states. By manipulating a single Fe atom onto the tip apex, signatures of the orbital nature of the…
We report an enhancement of superconducting transition temperature ($T_{\rm c}$) when Chromium (Cr) is substituted in excess at the Iron (Fe) site (FeCr$_x$Se, $x=$0.01, 0.02 and 0.03). There is a corresponding increase in the…
We study the crystal structure of the tetragonal iron selenide FeSe and its nematic phase transition to the low-temperature orthorhombic structure using synchrotron x-ray and neutron scattering analyzed in both real and reciprocal space. We…
BaFe$_2$S$_3$ is a quasi-one-dimensional antiferromagnetic insulator that becomes superconducting under hydrostatic pressure. The magnetic ordering temperature, $T_N$, as well as the presence of superconductivity have been found to be…
Iron-based superconductors are well known for their complex interplay between structure, magnetism and superconductivity. FeSe offers a particularly fascinating example. This material has been intensely discussed because of its extended…
Superconductivity with transition temperature Tc above 40 K was observed in protonated FeSe (Hy-FeSe) previously with the ionic liquid of EMIM-BF4 used in the electrochemical process. However, the real superconducting phase is not clear…
57Fe Moessbauer spectroscopy was applied to investigate the superconductor parent compound Fe(1+x)Te for x=0.06, 0.10, 0.14, 0.18 within the temperature range 4.2 K - 300 K. A spin density wave (SDW) within the iron atoms occupying regular…
We report on the first investigation of the quasiparticle local density of states and superconducting gap in the iron chalcogenide superconductor Fe$_{1+\delta}$Se$_{1-x}$Te$_{x}$ ($T_{\mathrm{c}} \sim 14$ K). The surface of a cleaved…
Inelastic neutron scattering was performed for an iron-based superconductor LaFeAsO0.9D0.1, where most of D (deuterium) replaces oxygen, while a tiny amount goes into interstitial sites. By first-principle calculation, we characterize the…
The surprising discovery of tripling the superconducting critical temperature of KFe$_2$As$_2$ at high pressures issued an intriguing question of how the superconductivity in the collapsed tetragonal phase differs from that in the…
The influence of hydrostatic pressure and ab-plane strain on the magnetic structure of FeTe is investigated from first principles. The results of calculations reveal a phase transition from antiferromagnetic double-stripe ordering at…
We examine the influence of the excess of interstitial Fe on the magnetic properties of Fe$_{1+y}$Te compounds. Because in iron chalcogenides the correlations are stronger than in the iron arsenides, we assume in our model that some of the…
Elastic neutron scattering simultaneously probes both the crystal structure and magnetic order in a material. Inelastic neutron scattering measures phonons and magnetic excitations. Here, we review the average composition, crystal structure…
hrough neutron diffraction experiments, including spin-polarized measurements, we find a collinear incommensurate spin-density wave with propagation vector $ \mathbf k = $ ($0.4481(4) \, \,0 \, \, \frac1 2$) at base temperature in the…
We report here that a new superconducting phase with much higher Tc has been found in K intercalated FeSe compound with excess Fe. We successfully grew crystals by precisely controlling the starting amount of Fe. Besides the superconducting…
It has recently been demonstrated that dynamical magnetic correlations measured by neutron scattering in iron chalcogenides can be described with models of short-range correlations characterized by particular {choices of four-spin…