Related papers: Multi-gap nodeless superconductivity in nickel cha…
Thermal transport measurements have been performed on single-crystalline Co-doped BaFe2As2 down to 0.1 K and under magnetic fields up to 7 T. Significant peak anomalies are observed in both thermal conductivity and thermal Hall conductivity…
Scanning tunneling spectroscopic studies of $Ba(Fe_{1-x}Co_x)_2As_2$ (x = 0.06, 0.12) single crystals reveal direct evidence for predominantly two-gap superconductivity. These gaps decrease with increasing temperature and vanish above the…
We report the electronic properties of superconductivity in the topological nodal-line semimetal PbTaSe$_2$. Angle-resolved photoemission measurements accompanied by band calculations confirmed the nodal-line band structure in the normal…
To elucidate the nature of the superconducting ground state of the geometrically frustrated pyrochlore KOs2O6 (Tc=9.6K), the thermal conductivity was measured down to low temperatures (~Tc/100). We found that the quasiparticle mean free…
We report on the superconducting (SC) properties of Y$_2$C$_3$ with a relatively high transition temperature $T_{\rm c}=15.7$ K investigated by $^{13}$C nuclear-magnetic-resonance (NMR) measurements under a magnetic field. The $^{13}$C…
Tunneling and optical transmission studies have been performed on superconducting samples of Rb3C60. At temperatures much below the superconducting transition temperature Tc the energy gap is 2 Delta=5.2 +- 0.2meV, corresponding to 2…
We report the observation of a pseudogap in the \emph{ab}-plane optical conductivity of underdoped Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ ($x = 0.2$ and 0.12) single crystals. Both samples show prominent gaps opened by a spin density wave (SDW)…
Alkali-fulleride superconductors with a maximum critical temperature Tc of 40 K exhibit similar electronic phase diagram with unconventional high-Tc superconductors where the superconductivity resides proximate to a magnetic Mott-insulating…
Superconductivity in the topological non-trivial Dirac semimetal PdTe$_2$ was recently shown to be type-I. We here report measurements of the relative magnetic penetration depth, $ \Delta \lambda$, on several single crystals using a high…
The optical properties of KCa$_{2}$Fe$_{4}$As$_{4}$F$_{2}$ (K12442, $T_c = 33.5$~K) and KCa$_{2}$(Fe$_{0.95}$Ni$_{0.05}$)$_{4}$As$_{4}$F$_{2}$ (Ni-K12442, $T_c = 29$~K) have been examined at a large number of temperatures. For both samples,…
The recently reported nickel carbide superconductor, body centered tetragonal $I4/mmm$ Th$_2$NiC$_2$ with T$_c$ = 8.5 K increasing to 11.2 K upon alloying Th with Sc, is found to have very fine structure in its electronic spectrum,…
The Weyl semimetal trigonal PtBi$_2$ has recently been identified as a promising candidate material for intrinsic topological surface superconductivity emerging from the Fermi arc states of the material with a sizeable superconducting gap.…
We report systematic ^{75}As-NQR and ^{139}La-NMR studies on nickel-pnictide superconductors LaNiAsO_{1-x}F_x (x=0, 0.06, 0.10 and 0.12). The spin lattice relaxation rate 1/T_1 decreases below T_c with a well-defined coherence peak and…
Layered ternary transition-metal chalcogenides have been focused as a vein of exploration for superconductors. In this study, TiGeTe$_{6}$ single crystals were synthesized and characterized by structural and valence state analyses and…
Superconductors based on transition metal dichalcogenides are of substantial current relevance, towards attaining topological superconductivity. Here we report a detailed study on the synthesis and electromagnetic characterization of…
Superconductivity and its underlying mechanisms are one of the most active research fields in condensed-matter physics. An important question is how to enhance the transition temperature $T_{\rm c}$ of a superconductor. In this respect, the…
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…
We study multigap superconductivity, with strong angular variations of one of the gaps, as appropriate for certain iron-based high-temperature superconductors. We solve the gap equations of this model and find that the nodes or zeroes in…
We observe a maximum in the conductance of Aluminum / n-GaAs junctions at temperatures 20 mK lower than the superconducting transition temperature. This is the first observation of a non- monotonic behavior of the conductance near the…
The layered compound $\mathrm{Ta_2NiSe_5}$ is a quasi-one-dimensional and narrow-gap semiconductor, which is proposed to undergo a transition to an excitonic insulator at $T_\mathrm{c}=326$ K. We found a clear anomaly at $T_\mathrm{c}$ in…