It is now well established that superconductivity in cuprates competes with charge modulations giving an electronic phase separation at nanoscale. More specifically, superconducting electronic current takes root in the available free space left by electronic charge ordered domains, called charge density wave (CDW) puddles. This means that CDW domain arrangement plays a fundamental role in the m...

In 1986, superconductivity—the ability to transport electrical current without significant resistance—was discovered in cuprate compounds. These materials have fascinated physicists ever since, in part because of the high critical temperatures (Tc’s) below which superconductivity is present and the consequent promise of technological applications. However, cuprate superconductivity also raises ...

Band structure calculations are presented for large supercells of Ba2CuO4 (BCO) with O-vacancies in planar or apical positions, and of superoxygenated La2CuO4 (LCO) with oxygen interstitials in the La2O2 layers. It is found that apical oxygen vacancies in BCO act as electron dopants and makes the electronic structure similar to that of hole doped LCO. Excess oxygen interstitials forming wires i...

A two-band model is used to study the phase separation in systems with different kinds of strongly correlated charge carrier, with a special emphasis on cuprate superconductors near optimum doping. We show that such a system can decompose into two metallic-like phases with more and less localized carriers. This phase separation is controlled by the energy splitting between the two bands. In cup...

We report a resistive investigation of superconductivity in the system La2 xSrxCuO4 y on samples which have been analysed by thermogravimetric techniques for oxygen deficiency determination. A maximum superconductive transition temperature is observed in La2 xSrxCuO4 y near the tetragonal-orthorhombic phase transition, together with a resurgence of high temperature superconductivity in non-subs...

Resonant inelastic X-ray scattering (RIXS) is a powerful probe of elementary excitations in solids. It now widely applied to study magnetic excitations. However, its complex cross-section means that RIXS has been more difficult interpret than neutron (INS). Here we report high-resolution measurements La2CuO4, the antiferromagnetic parent one system high-temperature superconductors. At high ener...