Related papers: Doping-dependent competition between superconducti…
We study the interplay of magnetic and superconducting order in single crystalline hole doped Ba1-xNaxFe2As2 using muon spin relaxation. We find microscopic coexistence of magnetic order and superconductivity. In a strongly underdoped…
We study the phase diagram of the t-J model using a mean field type approximation within the Baym-Kadanoff perturbation expansion for Hubbard $X$-operators. The line separating the normal state from a d-wave flux or bond-order state starts…
Recent measurements on extremely-underdoped YBa2Cu3O6+y [Phys. Rev. Lett. 99, 237003 (2007)] have allowed the critical temperature (T_c), superfluid density [rho_0 (T << T_c)] and dc conductivity [sigma_dc (T ~ T_c)] to be determined for a…
We establish the phase diagram of Eu$_{1-x}$La$_x$Fe$_2$As$_2$ system as a function of doping level x and the pressure by measuring the resistivity and magnetic susceptibility. The pressure can suppress the spin density wave (SDW) and…
In the cuprate superconductor $YBa_2Cu_3O_{6+x}$, hole doping in the $CuO_2$ layers is controlled by both oxygen content and the degree of oxygen-ordering. At the composition $\rm YBa_2Cu_3O_{6.35}$, the ordering can occur at room…
Ambient-pressure superconductivity in compressively strained bilayer nickelate films enables direct spectroscopic tests of pairing scenarios, yet how magnetism evolves with carrier doping remains largely unexplored. Here we use Ni…
In underdoped cuprates fluctuations of the phase of the superconducting order parameter play a role due to the small superfluid density. We consider the effects of phase fluctuations assuming the exchange of spin fluctuations to be the…
Microscopic, structural, transport and thermodynamic measurements of single crystalline Ba(Fe1-xTMx)2As2 (TM = Ni and Cu) series, as well as two mixed TM = Cu / Co series, are reported. All the transport and thermodynamic measurements…
The occurrence of superconductivity in proximity to various strongly correlated phases of matter has drawn extensive focus on their normal state properties, to develop an understanding of the state from which superconductivity emerges. The…
Charge-density wave (CDW) order is a key property of high-Tc cuprates, but its boundaries in the phase diagram and potential connections to other phases remain controversial. We report nuclear magnetic resonance (NMR) measurements in the…
Cuprate superconductors have many different atoms per unit cell. A large fraction of cells (5-25%) must be modified ("doped") before the material superconducts. Thus it is not surprising that there is little consensus on the superconducting…
Through partial substitution of Sm by U in SmFeAsO, a different member of the family of iron-based superconductors was successfully synthesized. X-ray diffraction measurements show that the lattice constants along the a and c axes are both…
The 2D superconductor-insulator transition in disordered ultrathin amorphous bismuth films has been tuned both by electrostatic electron doping using the electric field effect and by the application of parallel magnetic fields.…
We successfully tuned an underdoped ultrathin YBa2Cu3O7-x film into the overdoped regime by means of electrostatic doping using an ionic liquid as a dielectric material. This process proved to be reversible. Transport measurements showed a…
We report on measurements of the low temperature dependence of the magnetic penetration depth lambda_ab in several single crystals of La_2-xSr_xCuO_4, Bi_2Sr_2CaCu_2O_8 and YBa_2Cu_3O_6+x at various doping levels ranging from the under- to…
Application of a significantly large bias voltage to small Bi2Sr2CaCu2O8+x mesa structures leads to persistent doping of the mesas. Here we employ this effect for analysis of the doping dependence of the electronic spectra of Bi-2212 single…
We report the hole doping dependencies of the pseudogap phase energy scale, $2\Delta_{\rm PG}$, the anti-nodal (nodal) superconducting energy scales $2\Delta^{AN}_{\rm SC}$ ($2\Delta^{N}_{\rm SC}$) and the charge density wave energy scale,…
The superconductivity phase diagrams of electron doped cuprates of the form R(2-x)CexCuO4 (with R= La, Pr, Nd, Sm, and Eu) have been determined for cerium compositions 0 < x < 0.36 in a consistent series of epitaxial thin films grown by…
Emergency of superconductivity at the instabilities of antiferromagnetism (AFM), spin/charge density waves has been widely recognized in unconventional superconductors. In copper-oxide superconductors, spin fluctuations play a predominant…
High temperature superconductivity is a property of doped antiferromagnetic insulators. The electronic structure is inhomogeneous on short length and time scales, and, as the temperature decreases, it evolves via two crossovers, before long…