Related papers: Two-electronic component behavior in the multiband…
We report on the first local atomic structure study via the pair density function (PDF) analysis of neutron diffraction data and show a direct correlation of local coordinates to TC in the newly discovered superconducting FeSe1-xTex. The…
We present $^{77}$Se-NMR measurements on FeSe$_{1-x}$S$_x$ samples with sulfur content $x=0,9,15$ and $29\%$. Twinned nematic domains are observed in the NMR spectrum for all samples except $x=29\%$. The NMR spin-lattice relaxation rate…
The nature of the superconducting state in the recently discovered Fe-based superconductors1-3 is the subject of intense scrutiny. Neutron scattering investigations have already elucidated a strong correlation between magnetism and…
The superconducting properties of a recently discovered high $T_{\rm c}$ superconductor, Sr/ammonia-intercalated FeSe, have been measured using pulsed magnetic fields down to $4.\,\rm {K}$ and muon spin spectroscopy down to $1.5\,\rm K$.…
We present $^{77}$Se-NMR measurements on single-crystalline FeSe under pressures up to 2 GPa. Based on the observation of the splitting and broadening of the NMR spectrum due to structural twin domains, we discovered that static, local…
FeSe$_{1-x}$Te$_{x}$ superconductors manifest some intriguing electronic properties depending on the value of $x$. In FeSe single crystal, the nematic phase and Dirac band structure have been observed, while topological surface…
The interplay of orbital and spin degrees of freedom is the fundamental characteristic in numerous condensed matter phenomena, including high temperature superconductivity, quantum spin liquids, and topological semimetals. In iron-based…
We have performed $^{125}$Te NMR on a single crystal of the novel layered superconductor Fe$_{1.04}$Te$_{0.67}$Se$_{0.33}$ for the first time. The spin parts of the Knight shifts for both $H // a$, $H // c$ are suppressed in the…
Magnetic fluctuations in the molecular-intercalated FeSe superconductor Li{x}(ND2){y}(ND3){1-y}Fe2Se2 (Tc = 43K) have been measured by inelastic neutron scattering from a powder sample. The strongest magnetic scattering is observed at a…
The magnetotransport behaviour inside the nematic phase of bulk FeSe reveals unusual multiband effects that cannot be reconciled with a simple two-band approximation proposed by surface-sensitive spectroscopic probes. In order to understand…
We study the electronic properties of the $\textrm{Fe}\textrm{Se}_{1-x}\textrm{Te}_x$ system ($x=0$, 0.25, 0.5, 0.75, and 1) from the perspective of X-ray spectroscopy and density functional theory (DFT). The analysis performed on the…
We investigate superconductivity in a two-band system with an electron- and hole-like band, where one of the bands is away from the Fermi level (or incipient). We argue that the incipient band contributes significantly to spin-fluctuation…
The high Tc superconductor FeTe0.55Se0.45 has recently been shown to support a surface state with topological character. Here we use low-energy laser-based ARPES with variable light polarization, including both linear and circular…
A number of recent experiments indicate that the iron-chalcogenide FeSe provides the long-sought possibility to study bulk superconductivity in the cross-over regime between the weakly coupled Bardeen--Cooper--Schrieffer (BCS) pairing and…
We study the crystalline and electronic properties of the $\textrm{Fe}_{1-x}\textrm{Co}_x\textrm{Se}$ system ($x=0$, 0.25, 0.5, 0.75, and 1.0) using X-ray diffraction, X-ray spectroscopy and density functional theory. We show that the…
The superconducting critical temperature, $T_{\rm c}$, of FeSe can be dramatically enhanced by intercalation of a molecular spacer layer. Here we report on a $^{77}$Se, $^7$Li and $^1$H nuclear magnetic resonance (NMR) study of the powdered…
We report an investigation into the superconducting and magnetic properties of Fe_{1+y}Se_{x}Te_{1-x} single crystals by magnetic susceptibility, muon spin rotation, and neutron diffraction. We find three regimes of behavior in the phase…
Superconductivity in alkali-intercalated iron selenide, with T_c's of 30K and above, may have a different origin than that of the other Fe-based superconductors, since it appears that the Fermi surface does not have any holelike sheets…
In high-superconducting transition temperature ($T_{\rm c}$) iron-based superconductors, interband sign reversal ($s_{\rm \pm}$) and sign preserving ($s_{\rm ++}$) $s$-wave superconducting states have been primarily discussed as the…
Recently topological superconducting states has attracted a lot of interest. In this work, we consider a topo- logical superconductor with $Z_2$ topological mirror order [1] and s$\pm$-wave superconducting pairing symmetry, within a…