Related papers: FeTe$_{0.55}$Se$_{0.45}$: a multiband superconduct…
Iron chalcogenide superconductors are multi-band systems with strong electron correlations. Here we use angle-resolved photoemission spectroscopy to study band dependent correlation effects in single-layer FeSe/Nb:BaTiO3/KTaO3, a new iron…
The optical properties of the iron-chalcogenide superconductor K{0.8}Fe{2-y}Se2, with a critical temperature Tc = 31 K, have been measured over a wide frequency range in the a-b planes above and below Tc. The conductivity is incoherent at…
We have performed a low temperature scanning tunneling microscopy and spectroscopy study of the iron chalcogenide superconductor FeSe_{0.4}Te_{0.6} with T_{C}~14 K. Spatially resolved measurements of the superconducting gap reveal…
The temperature-dependence of the in-plane optical properties of (CaFe$_{1-x}$Pt$_{x}$As)$_{10}$Pt$_{3}$As$_{8}$ have been investigated for the undoped ($x=$0) parent compound, and the optimally-doped ($x=$0.1) superconducting material…
The crystal structure of the superconductor FeSe0.44Te0.56 was redetermined by high-resolution X-ray single crystal diffraction at 173 K (anti-PbO-type, P4/nmm, a=3.7996(2), c=5.9895(6) A, R1=0.022, wR2=0.041, 173 F^2). Significantly…
The iron-chalcogenide high temperature superconductor Fe(Se,Te) (FST) has been reported to exhibit complex magnetic ordering and nontrivial band topology which may lead to novel superconducting phenomena. However, the recent studies have so…
We report on a comprehensive study of the transport, specific heat, magnetic susceptibility and optical spectroscopy on single crystal of Fe$_{1.05}$Te. We confirm that Fe$_{1.05}$Te undergoes a first-order phase transition near 65 K.…
We report the synthesis and superconducting properties of a new transition-metal chalcogenide Ta$_2$PdSe$_5$. The measurements of resistivity, magnetization, and specific heat reveal that Ta$_2$PdSe$_5$ is a bulk superconductor with $T_c$…
Polycrystalline samples of FeSe$_{0.5}$Te$_{0.5}$ were synthesized using a conventional solid-state reaction method. The onset of bulk superconductivity transition was confirmed by SQUID magnetometry at 12.5~K. $^{57}$Fe M\"ossbauer spectra…
The superconducting diode effect (SDE) - the asymmetry of critical currents with respect to current direction - is a pivotal advancement in non-reciprocal superconductivity. While SDE has been realized in diverse systems, a fundamental…
Bulk FeSe is superconducting with a critical temperature $T_c$ $\cong$ 8 K and SrTiO$_3$ is insulating in nature, yet high-temperature superconductivity has been reported at the interface between a single-layer FeSe and SrTiO$_3$. Angle…
This article reviews recent experimental investigations on two binary Fe-chalcogenides: FeSe and Fe$_{1+y}$Te. The main focus is on synthesis, single crystal growth, chemical composition, as well as on the effect of excess iron on…
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…
We report microwave surface impedances of FeSe$_{0.4}$Te$_{0.6}$ single crystals measured at 12, 19, and 44 GHz. The penetration depth exhibits a power law behavior, $\delta \lambda_L=\lambda_L (T)-\lambda_L (0) \propto CT^n$ with an…
We investigate the high-pressure phase of the iron-based superconductor FeSe$_{0.89}$S$_{0.11}$ using transport and tunnel diode oscillator studies. We construct detailed pressure-temperature phase diagrams that indicate that outside of the…
The electrodynamic properties of Ba(Fe$_{0.92}$Co$_{0.08})_2$As$_{2}$ and Ba(Fe$_{0.95}$Ni$_{0.05})_As$_{2}$ single crystals have been investigated by reflectivity measurements in a wide frequency range. In the metallic state, the optical…
The bulk polycrystalline sample FeSe1/2Te1/2 is synthesized by solid state reaction route in an evacuated sealed quartz tube at 750 oC. The presence of superconductivity is confirmed through magnetization/thermoelectric/resistivity studies.…
Superconducting iron chalcogenide FeSe has the simplest crystal structure among all the Fe-based superconductors. Unlike other iron pnictides, FeSe exhibits no long range magnetic order accompanying the tetragonal-to-orthorhombic structural…
Among the mysteries surrounding unconventional, strongly correlated superconductors is the possibility of spatial variations in their superfluid density. We use atomic-resolution Josephson scanning tunneling microscopy to reveal a strongly…
We report an infrared spectroscopy study of a 200 nm thick FeSe$_{0.5}$Te$_{0.5}$ film grown on LaAlO$_3$ with T$_c$=13.7 K. We analyze the 20 K normal state absolute reflectance R$_N$ measured over a broad infrared range and the…