相关论文: S-wave Superconductivity in Optimally Doped SrTi$_…
SrTiO$_3$ exhibits a superconducting dome upon doping with Nb, with a maximum critical temperature \mbox{$T_\mathrm{c} \approx 0.4$~K}. Using microwave stripline resonators at frequencies from 2 to 23~GHz and temperatures down to 0.02~K, we…
We present resistivity and magnetization measurements on proton-irradiated crystals demonstrating that the superconducting state in the doped topological superconductor Nb$_x$Bi$_2$Se$_3$ (x = 0.25) is surprisingly robust against…
A single crystal of isovalently substituted Ba(Fe$_{1-x}$Ru$_{x}$)$_2$As$_2$ ($x=0.24$) was sequentially irradiated with 2.5 MeV electrons up to a maximum dose of $2.1 \times 10^{19}$ electrons/cm^2. The electrical resistivity was measured…
Nb doped SrTiO3, the first discovered two-gap superconductor, is shown to be the most unconventional one of the known multiband superconductors, since the smaller of the two superconducting gaps follows a non BCS temperature dependence.…
Irradiation with 2.5 MeV electrons at doses up to 5.2 $\times$10$^{19}$ electrons/cm$^2$ was used to introduce point-like defects in single crystals of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ with $x=$ 0.19 ($T_c=$ 14 K), $x=$ 0.26 ($T_c=$ 32 K) and…
The London penetration depth was measured in optimally doped Ba0.6K0.4Fe2As2 crystals, with and without columnar defects produced by 1.4 GeV 208Pb irradiation. The low temperature behavior of unirradiated samples was consistent with a fully…
We report on the determination of the electronic heat capacity of a slightly overdoped (x = 0.075) Ba(Fe1-xCox)2As2 single crystal with a Tc of 21.4 K. Our analysis of the temperature dependence of the superconducting-state specific heat…
Controlled point-like disorder introduced by 2.5 MeV electron irradiation was used to probe the superconducting state of single crystals of \CaKx\ superconductor at $x = 0$ and 0.05 doping levels. Both compositions show an increase of the…
We use inelastic neutron scattering to probe magnetic excitations of an optimally electron-doped superconductor Nd$_{1.85}$Ce$_{0.15}$CuO$_{4-\delta}$ above and below its superconducting transition temperature $T_c=25$ K. In addition to…
We report on superconductivity in single crystals of SrTiO$_{3-\delta}$ with carrier densities $\textit{n} < 1.4 \times10^{18}cm^{-3}$, where only a single band is occupied. For all samples in this regime, the resistive transition occurs at…
The investigation of the temperature dependences of microwave surface impedance and complex conductivity of V3Si single crystals with different stoichiometry allowed to observe a number of peculiarities which are in remarkable contradiction…
We developed a theory of electric and thermoelectric conductivity of lightly doped SrTiO$_3$ in the non-degenerate region $k_B T \geq E_F$, assuming that the major source of electron scattering is their interaction with soft transverse…
Polycrystalline Sr1-xNdxFeAsF samples were prepared at various Nd-doping levels using both a stoichiometric mixture of the starting materials and in slight excess amounts of FeAs. Susceptibility and resistivity of the samples were studied…
We present the first study of thermal conductivity in superconducting SrTi$_{1-x}$Nb$_{x}$O$_{3}$, sufficiently doped to be near its maximum critical temperature. The bulk critical temperature, determined by the jump in specific heat,…
We report a systematic study of the normal-state and superconducting properties of single crystal Pb$_{1-x}$Sn$_{x}$TaSe$_{2}$ $(0\leq x \leq 0.23)$. Sn doping enhances the superconducting temperature $T_{c}$ up to 5.1 K while also…
The London penetration depth, $\lambda(T)$, was measured in a single crystal V$_{3}$Si. The superfluid density obtained from this measurement shows a distinct signature of two almost decoupled superconducting gaps. This alone is…
The superconductor Sn_{1-x}In_{x}Te is a doped topological crystalline insulator and has become important as a candidate topological superconductor, but its superconducting phase diagram is poorly understood. By measuring about 50 samples…
Electron-doped infinite-layer Sr$_{1-x}$Eu$_{x}$CuO$_{2+y}$ films over a wide doping range have been prepared epitaxially on SrTiO$_3$(001) using reactive molecular beam epitaxy. In-plane transport measurements of the single crystalline…
We report the $^{121/123}$Sb-NMR/nuclear quadrupole resonance (NQR) measurements on the newly-discovered superconductor BaTi$_2$Sb$_2$O with a two-dimensional Ti$_2$O square-net layer formed with Ti$^{3+}$ (3$d^1$). NQR measurements…
We investigate validity of Anderson's theorem (AT) for disordered s-wave superconductors in a negative U Hubbard model with random on-site energies, $\epsilon_{i}$. The superconducting critical temperature, $T_{c}$, is calculated in the…