Related papers: Disorder-sensitive node-like small gap in FeSe
The field and temperature dependencies of the longitudinal and Hall resistivity have been measured for FeSe${}_{1-x}$S${}_{x}$ (x=0.04, 0.09 and 0.19) single crystals. The sample FeSe${}_{0.81}$S${}_{0.19}$ does not show a transition to an…
We present our investigations on the superconducting properties of monolayers of FeSe$_{0.5}$Te$_{0.5}$ grown on the 3D topological insulator Bi$_{2}$Se$_{1.2}$Te$_{1.8}$ using low temperature scanning tunneling spectroscopy (STS). While…
We report the successful synthesis of FeSe$_{1-x}$S$_{x}$ single crystals with $x$ ranging from 0 to 1 via a hydrothermal method. A complete phase diagram of FeSe$_{1-x}$S$_{x}$ has been obtained based on resistivity and magnetization…
The origin of the high-temperature superconducting state observed in FeSe thin films, whose phase diagram displays no sign of magnetic order, remains a hotly debated topic. Here we investigate whether fluctuations arising due to the…
Using the "break-junction" technique we prepared and studied superconductor - constriction - superconductor nanocontacts in polycrystalline samples of Fe-based superconductors CeO$_{0.88}$F$_{0.12}$FeAs (Ce-1111; $T_C^{\rm bulk} = 41 \pm 1…
Electronic properties of FeSe can be tuned by various routes. Here, we present a comprehensive study on the evolution of the superconductivity and nematicity in FeSe with thickness from bulk single crystal down to bilayer ($\sim$ 1.1 nm)…
In the iron based superconductors, one of the on-going frontier studies is about the pairing mechanism. The recent interest concerns the high temperature superconductivity and its intimate reason in the monolayer FeSe thin films. The…
Using two experimental techniques, we studied single crystals of the 122-FeAs family with almost the same critical temperature, Tc. We investigated the temperature dependence of the lower critical field of a single crystal under static…
Understanding superconductivity requires detailed knowledge of the normal electronic state from which it emerges. A nematic electronic state that breaks the rotational symmetry of the lattice can potentially promote unique scattering…
Recent studies of FeSi$_{(1-x)}$Ge$_x$, which found a transition from an insulating to a magnetic metallic state near $x$=0.25, have revived the discussion about the role of strong correlation in these systems. Here are spin polarized band…
Planar tunneling junctions of the presumably unconventional superconductor FeSe were prepared and investigated. The junctions consisted of FeSe/AlOx/Ag multilayers patterned lithographically into mesa structures. Bias voltage dependent…
In order to investigate details of the superconducting (SC) gap in the iron-chalcogenide superconductors, the specific heat, C, of FeSe_1-x_Te_x_ with x=0.6-1 has been measured in magnetic fields. Using the two-gap model, it has been found…
Since the discovery of high-Tc LaO_1-xF_xFeAs, and other such systems based on FeAs layers, several proposals have been made for the superconducting order parameter Delta_k, on both phenomenological and microscopic grounds. Here we discuss…
High-temperature superconductivity and a wide variety of exotic superconducting states discovered in FeSe-based materials have been at the frontier of research on condensed matter physics over the past decade. Unique properties originating…
Bulk FeSe is a special iron-based material in which superconductivity emerges inside a well-developed nematic phase. We present a microscopic model for this nematic superconducting state, which takes into account the mixing between $s-$wave…
We report the temperature evolution of the detailed electronic band structure in FeSe single-crystals measured by angle-resolved photoemission spectroscopy (ARPES), including the degeneracy removal of the $d_{xz}$ and $d_{yz}$ orbitals at…
We report a systematic study of superconductivity on Fe1-xZnxSe single crystals synthesized over a broad Zn doping range (x = 0-0.023). High-quality single crystals across all compositions range exhibit superconducting transitions, while…
We probe the superconducting order parameter of the organic-ion-intercalated FeSe-based superconductor (tetrabutyl ammonium)$_{0.3}$FeSe [(TBA)$_{0.3}$FeSe] using muon-spin relaxation/rotation ($\mu$SR). Zero-field $\mu$SR measurements show…
We report high-sensitivity microwave measurements of the in-plane penetration depth $\lambda_{ab}$ and quasiparticle scattering rate $1/\tau$ in several single crystals of hole-doped Fe-based superconductor Ba$_{1-x}$K$_x$Fe$_2$As$_2$…
We utilize steady-state and transient optical spectroscopies to examine the responses of nonthermal quasiparticles with respect to orbital modifications in normal-state iron-chalcogenide superconductors. The dynamics shows the emergence of…