Related papers: Dumbbell Defects in FeSe Films: A Scanning Tunneli…
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…
In FeSe-derived superconductors, the lack of a systematic and clean control on the carrier concentration prevents the comprehensive understanding on the phase diagram and the interplay between different phases. Here by K dosing and angle…
We performed $^{77}$Se-NMR measurements on FeSe$_{1-x}$S$_x$, ($x$ = 0.12) up to 3.0 GPa at an applied magnetic field of 6.02 T, and found that the superconducting (SC) phase exhibits a remarkable double-dome structure in the…
Possible superconductivity in recently discovered (Tl,K)Fe$_x$Se$_2$ compounds is studied from the viewpoint of doped Mott insulator. The Mott insulating phase is examined to be preferred in the parent compound at $x=1.5$ due to the…
Although the pairing mechanism of the Fe-based superconductors (FeSCs) has not yet been settled with a consensus, as to the pairing symmetry and the superconducting (SC) gap function, the abundant majority of experiments are supporting for…
Iron-based superconductors (FBS) comprise several families of compounds having the same atomic building blocks for superconductivity, but large discrepancies among their physical properties. A longstanding goal in the field has been to…
The discovery of high-temperature superconductivity in Fe-based compounds [1,2] has triggered numerous investigations on the interplay between superconductivity and magnetism [3] and, more recently, on the enhancement of transition…
Finding of unconventional superconductivity (USC) in FeSe in an electronic "normal" state with broken $C_{4v}$ rotational symmetry testifies to the diversity of pairing states in Fe-based superconductors. Moreover, such USC emerges as a…
Structural distortions and imperfections are a crucial aspect of materials science, on the macroscopic scale providing strength, but also enhancing corrosion and reducing electrical and thermal conductivity. At the nanometre scale,…
Using the coherent-potential approximation, we have studied the effects of excess Fe, Se-deficiency, and substitutions of S, Te on Se sub-lattice and Co, Ni and Cu on Fe sub-lattice in FeSe. Our results show that (i) a small amount of…
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 transport and superconducting properties - namely resistivity, magnetoresistivity, Hall effect, Seebeck effect, thermal conductivity, upper critical field - of two different families of Fe-based superconductors, which can be…
Structural investigations by means of transmission electron microscopy (TEM) on KFexSe2 with 1.5 \leq x \leq 1.8 have revealed a rich variety of microstructure phenomena, the KFe1.5Se2 crystal often shows a superstructure modulation along…
We present a microscopic investigation of frequently observed impurity-induced states in stoichiometric LiFeAs using low temperature scanning tunneling microscopy and spectroscopy (STM/STS). Our data reveal seven distinct well defined…
At present, there is still no consistent interpretation of the normal and superconducting properties of Fe-based superconductors (FeSCs). The strength of the el-el interaction and the role of correlation effects are under debate. Here, we…
The pairing symmetry of the superconducting order parameter in iron-based superconductors has been a subject of debate, with various models proposing s-wave, d-wave, and mixed combinations as possible candidates. Here we probe the pairing…
Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate twin boundaries in stoichiometric FeSe films grown by molecular beam epitaxy. Twin boundaries can be unambiguously identified by imaging the 90{\deg}…
The Weyl semimetal MoTe$_2$ offers a rare opportunity to study the interplay between Weyl physics and superconductivity. Recent studies have found that Se substitution can boost the superconductivity up to 1.5K, but suppress the Td…
Nematic phases, where electrons in a solid spontaneously break rotational symmetry while preserving the translational symmetry, exist in several families of unconventional superconductors [1, 2]. Although superconductivity mediated by…
We report on the emergence of two disconnected superconducting domes in alkali-metal potassium (K)-doped FeSe ultra-thin films grown on graphitized SiC(0001). The superconductivity exhibits hypersensitivity to K dosage in the lower-Tc dome,…