Charge doping of iron-pnictide superconductors leads to collective pinning of flux vortices, whereas isovalent doping does not. Moreover, flux pinning in the charge-doped compounds is consistently described by the mean-free path fluctuations introduced by the dopant atoms, allowing for the extraction of the elastic quasiparticle scattering rate. The absence of scattering by dopant atoms in isov...

Low temperature properties of antiferromagnetic two-leg spin-1/2 ladders with bond randomness and site dilution ~or doping with nonmagnetic impurities! are studied using the real-space renormalization-group technique. We find that for nonzero dopant concentrations the systems are driven into a phase dominated by large effective spins, i.e., the large spin phase. The susceptibility follows a uni...

The characteristic association time constant describing the formation of iron-acceptor pairs in crystalline silicon has been measured for samples of various p-type dopant concentrations and species B, Ga, and In near room temperature. The results show that the dopant species has no impact on the pairing kinetics, suggesting that the pairing process is entirely limited by iron diffusion. This co...

A nematic elastomer film with a 90 o twist orientation between the top and bottom surfaces is prepared by chiral imprinting methods. The reactive achiral nematic monomers and crosslinkers are photopolymerized in the presence of a controlled amount of unreactive chiral dopant. The elastomer films possess a 90 o twist orientation even after the removal of the chiral dopant. The films exhibit an e...

We provide a fundamental insight into the microscopic mechanisms of the aging processes. Using large-scale molecular dynamics simulations of the prototypical ferroelectric material PbTiO_{3}, we demonstrate that the experimentally observed aging phenomena can be reproduced from intrinsic interactions of defect dipoles related to dopant-vacancy associates, even in the absence of extrinsic effect...

Field ionization of trimethylamine and of N,N-dimethylaniline doped into xenon is presented as a function of xenon number density up to the density of the triple point liquid, both at noncritical temperatures and along the critical isotherm. These data exhibit a decrease in the xenon induced shift of the dopant ionization energy near the xenon critical point. The energy of the quasi-free electr...

Hexagonal GdF3 is a more efficient phosphor host compared with the traditional orthorhombic form but the hexagonal phase is thermodynamically unstable at room temperature. Herein, we present a strategy to stabilize hexagonal GdF3 by doping with alkaline-earth ions in a mild hydrothermal reaction system. The selection of the dopant, effect of the dopant amount and the mechanism of the phase tran...

In this work, diffusion processes in thermally connected cylindrical fibers with weakly guiding and circular cross-section, that is, telecommunication fibers, have been presented. There have been discussed diffusion distributions of the core dopant of fibers spliced at T ≈ 2000 °C. Gaussian approximations of the core dopant concentration distribution and refractive index in the connecting area ...