Related papers: Theory for doping trends in titanium oxypnictide s…
In high-temperature cuprate superconductors, the anti-ferromagnetic spin fluctuations are thought to have a very important role in naturally producing an attractive interaction between the electrons in the $d$-wave channel. The connection…
We present low-temperature thermal conductivity measurements on the cuprate Tl_2Ba_2CuO_{6+delta} throughout the overdoped regime. In the T -> 0 limit, the thermal conductivity due to d-wave nodal quasiparticles provides a bulk measurement…
A new layered Ti-based pnictide oxide superconductor, Ba1-xNaxTi2Sb2O (0.0 <= x <= 0.33), is reported. X-ray studies reveal it crystallizes in the tetragonal CeCr2Si2C structure. The undoped parent compound, BaTi2Sb2O (P4/mmm;…
The recently discovered FeAs-based superconductors are a new, promising set of materials for both technological as well as basic research. They offer transition temperatures as high as 55 K as well as essentially isotropic and extremely…
The temperature and magnetic field dependence of the in-plane thermal conductivity $\kappa$ of the iron-arsenide superconductor Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ was measured down to $T \simeq 50$ mK and up to $H = 15$ T as a function of Co…
We investigated the optical spectrum of Ba(Fe1-xCox)2As2 single crystals with various doping levels. It is found that the low-energy optical conductivity spectrum of this system can be decomposed into two components: a sharp Drude term and…
We report an angular quantum oscillation study of Tl_2Ba_2CuO_{6+delta} for two different doping levels (Tc = 10K and 26 K) and determine the Fermi surface size and topology in considerable detail. Our results show that Fermi liquid…
SrTiO$_{3}$ is an incipient ferroelectric and an exceptionally dilute superconductor with a dome-like dependence on carrier concentration. Stabilization of a polar phase through chemical substitution or strain significantly enhances the…
For YBa_2Cu_3O_{6+\delta} and Bi_2Sr_2CaCu_2O_8 superconductors, electronic Raman scattering from high- and low-energy excitations has been studied in relation to the hole doping level, temperature, and energy of the incident photons. For…
We report on the synthesis and the physical properties of Ba1-xRbxTi2Sb2O (x < 0.4) by x-ray diffraction, SQUID magnetometery, resistivity and specific heat measurements. Upon hole doping by substituting Ba with Rb, we find…
Doping effect of diamond nanoparticles on the superconducting properties of MgB2 bulk material has been studied. It is found that the superconducting transition temperature Tc of MgB2 is suppressed by the diamond-doping, however, the…
We report the effect of Sn doping on the transport properties of the topological insulator Bi_{2}Te_{2}Se studied in a series of Bi_{2-x}Sn_{x}Te_{2}Se crystals with 0 \leq x \leq 0.02. The undoped stoichiometric compound (x = 0) shows an…
Chemical doping of topological materials may provide a possible route for realizing topological superconductivity. However, all such cases known so far are based on chalcogenides. Here we report the discovery of superconductivity induced by…
A dome-shaped phase diagram of superconducting critical temperature upon doping is often considered as a hallmark of unconventional superconductors. This behavior, observed in two-dimensional electron gases in $\mathrm{SrTiO}_3$-based…
Graphene has exhibited a wealth of fascinating properties, but is also known not to be a superconductor. Remarkably, we show that graphene can be made a conventional Bardeen-Cooper-Schrieffer superconductor by the combined effect of charge…
In the spin-excitation-mediated pairing mechanism for superconductivity, the geometric frustration effects not only the spin configuration but also the superconducting-state properties. Within the framework of the kinetic-energy-driven…
The electronic structure of the intercalated iron-based superconductor Ba2Ti2Fe2As4O (Tc - 21.5 K) has been investigated by using angle-resolved photoemission spectroscopy and combined local density approximation and dynamical mean field…
The cuprate superconductors distinguish themselves from the conventional superconductors in that a small variation in the carrier doping can significantly change the superconducting transition temperature (T_c), giving rise to a…
Motivated by recent experimental investigations of the isovalent doping iron-based superconductors LaFe(AsxP1-x)O1-yFy and NdFe(AsxP1-x)O1-yFy we theoretically study the correlation between the local lattice structure, the Fermi surface,…
We study a microscopic mechanism of Fe-pnictide superconductor, considering the screening effects of Coulomb interaction in addition to the conventional spin-fluctuation mechanism. It is shown that, by electron doping, the transition…