Related papers: Nodal Superconducting Gap in $\beta$-FeS
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…
We report on the Andreev spectroscopy and specific heat of high-quality single crystals BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$. The intrinsic multiple Andreev reflection spectroscopy reveals two anisotropic superconducting gaps $\Delta_L \approx…
We investigate the electronic properties and the superconducting gap characteristics of a single crystal of hole-doped 122 Fe-pnictide Ba$_{0.65}$Na$_{0.35}$Fe$_2$As$_2$ by means of specific heat measurements. The specific heat exhibits a…
The temperature, field, and field-orientation dependences of the electronic specific heat Ce of the ironpnictide superconductor KFe2As2 have been investigated. Thermodynamic evidence of the presence of line nodes is obtained from the T and…
We report local probe ($\mu$SR) measurements on the recently discovered tetragonal FeS superconductor which has been predicted to be electronically very similar to superconducting FeSe. Most remarkably, we find that low moment…
In hole-doped high-Tc superconductors, thermal conductivity increases drastically just below Tc, which has been considered as a hallmark of a nodal gap. In contrast, such a coherence peak in thermal conductivity is not visible in…
The symmetry and structure of the superconducting gap in the Fe-based superconductors are the central issue for understanding these novel materials. So far the experimental data and theoretical models have been highly controversial. Some…
Low-temperature specific heat (SH) is measured on Ba(Fe$_{1-x}$Co$_{x}$)$_2$As$_2$ single crystals in a wide doping region under different magnetic fields. For the overdoped sample, we find the clear evidence for the presence of $T^2$ term…
We present the first experimental results of the lower critical field $H_{c1}$ of the newly discovered F-doped superconductor LaO$_{0.9}$F$_{0.1}$FeAs (F-LaOFeAs) by global and local magnetization measurements. It is found that $H_{c1}$…
Point-contact Andreev reflection spectroscopy at low temperatures and high magnetic fields has been performed on a noncentrosymmetric La$_3$Se$_4$ superconductor with a critical temperature $T_c$ = 8 K. Two superconducting energy gaps…
To examine the so-called small pseudogap and the superconducting (SC) condensation energy U(0), the electronic specific heat Cel was measured on La_{2-x}Sr_{x}CuO_{4} up to ~120K. In samples with doping level p (=x) less than ~0.2, small…
We present low-temperature specific heat of the electron-doped Ba(Fe$_{0.9}$Co$_{0.1}$)$_{2}$As$_{2}$, which does not show any indication of an upturn down to 400 mK, the lowest measuring temperature. The lack of a Schottky-like feature at…
The heat capacity of a 2H-NbS2 single crystal has been measured by a highly sensitive ac technique down to 0.6 K and in magnetic fields up to 14 T. At very low temperatures data show excitations over an energy gap (2DS/kBTc \approx 2.1)…
Knowledge of the doping (x)-temperature (T) phase diagram of Fe-based superconductors is crucial in understanding the mechanism of high transition temperature superconductivity. Here, we measured the Se doping dependence of the magnetic…
Experimental evidence of novel phenomena in hydrogenated graphite fibers is found. An indirect excitonic mechanism is likely leading to a SC state below the temperature Tc = 50 K, where the gap is divergent. Analysis of the gap within the…
Over the past two decades, unconventional superconductivity with gap symmetry other than s-wave has been found in several classes of materials, including heavy fermion (HF), high-T_c, and organic superconductors. Unconventional…
We performed thermal conductivity measurements on a single crystal of the ferromagnetic superconductorUCoGe under magnetic field. Two different temperature dependencies of the thermal conductivity are observed, for H//b linear at low…
This paper presents the results of specific-heat and magnetization measurements, in particular their field-orientation dependence, on the first discovered heavy-fermion superconductor CeCu$_2$Si$_2$ ($T_{\rm c} \sim 0.6$ K). We discuss the…
Low-temperature (down to $\sim$ 50 mK) thermal conductivity measurements with the heat flow direction along the inter-plane tetragonal $c$-axis, $\kappa_c$, were used to study the superconducting state of heavy fermion CeIrIn$_5$.…
We have measured the low-energy quasiparticle excitation spectrum of the electron doped high-temperature superconductors (HTS) Nd(1.85)Ce(0.15)CuO(4-y) and Pr(1.85)Ce(0.15)CuO(4-y) as a function of temperature and applied magnetic field…