Related papers: Electronic crossover suggested by Raman scattering…

Several decades after the discovery of superconductivity in bismuthates, the strength of their electron-phonon coupling and its evolution with doping remain puzzling. To clarify these issues, polycrystalline hole-doped…

It is argued that the origin of the buckling of the CuO$_{2}$ planes in certain cuprates as well as the strong electron-phonon coupling of the $B_{1g}$ phonon is due to the electric field across the planes induced by atoms with different…

The condensation of paired fermions into superfluid states changes progressively depending on the coupling strength. At the midpoint of the crossover between Bardeen--Cooper--Schrieffer (BCS) weak-coupling and Bose--Einstein condensate…

Both electronic Raman scattering (ERS) and angle-resolved photoemission spectra (ARPES) revealed two energy scales for the gap in different momentum spaces in the cuprates. However, the interpretations were different, and the gap values…

The pseudogap is one of the most pervasive phenomena of high temperature superconductors. It is attributed either to incoherent Cooper pairing setting in above the superconducting transition temperature Tc, or to a hidden order parameter…

Electronic Raman scattering experiments in a wide variety of materials (ranging from mixed-valence materials to Kondo insulators to high-temperature superconductors) show anomalous behavior in the B_{1g} channel when the system is on the…

In this paper, we review some of our ARPES results on the superconducting and pseudo gaps in Bi2Sr2CaCu2O8+x. We find that optimally and overdoped samples exhibit a d-wave gap, which closes at the same temperature, Tc, for all k points. In…

We study the quantum transition from an antiferromagnet to a superconductor in a model for electron- and hole-doped cuprates by means of a variational cluster perturbation theory approach. In both cases, our results suggest a tendency…

The polarized Raman scattering spectra from freshly cleaved $ab$, $ac$, and $bc$ surfaces of high quality twin free YBa$_2$Cu$_3$O$_{6.5}$ (Ortho-II) single crystals ($T_c$=57.5 K and $\Delta T = 0.6$ K) were studied between 80 and 300 K.…

In present work the conductivity in the basis plane of YBaCuO single crystals slightly doped by Al and Pr with a pre-specified topology of twin boundaries has been investigated. The excess conductivity for the analyzed samples shows…

Recent polarized neutron scattering experiments on $YBa_2 Cu_3 O_7$ have revealed a sharp spectral peak at the $(\pi,\pi)$ in reciprocal lattice centered around the energy transfer of $41\ meV$. We offer a theoretical explanation of this…

We report a detailed Raman scattering study of the lattice dynamics in detwinned single crystals of the underdoped high temperature superconductor YBa2Cu3O6+x (x=0.75, 0.6, 0.55 and 0.45). Whereas at room temperature the phonon spectra of…

A detailed inelastic neutron scattering study of the overdoped high temperature copper oxide superconductor ${Y_{0.9}Ca_{0.1}Ba_{2}Cu_3O_{7}}$ reveals two distinct magnetic resonant modes in the superconducting state. The modes differ in…

A systamatic quantitative comparison of ''pseudogap'' values obtained from the analysis of charge and spin excitation spectroscopies in underdoped YBa2Cu3O7-x using a temperature-independent gap shows two distinct excitations, one visible…

Electronic Raman scattering in Tl-2201 has been investigated in order to test whether the scattering cross-section in high temperature superconductors depends on the number of CuO2-planes, i.e. sheets or specific details of the Fermi…

We use inelastic neutron scattering with spin polarization analysis to study the magnetic excitations in the normal and superconducting states of YBa2Cu3O6.9. Polarization analysis allows us to determine the spin polarization of the…

The nature of the pseudogap phase of cuprate high-temperature superconductors is a major unsolved problem in condensed matter physics. We studied the commencement of the pseudogap state at temperature T* using three different techniques…

Scanning tunneling spectroscopy (STS) studies reveal long-range spatial homogeneity and predominantly $d_{x^2-y^2}$-pairing spectral characteristics in under- and optimally doped $\rm YBa_2Cu_3O_{7-\delta}$ superconductors, whereas STS on…

We study the superconducting transition in a two-dimensional electron gas with strong Rashba spin-orbit coupling. We assume low electron density, such that only the majority spin band participates in the transition. We show that the…

We report inelastic light scattering results on the stoichiometric and fully ordered superconductor CaKFe$_4$As$_2$ as a function of temperature and light polarization. In the energy range between 10 and 315 cm$^{-1}$ (1.24 and 39.1 meV) we…