HISTORY OF HIGHTEMPERATURE SUPERCONDUCTIVITY After superconductivity was discovered by Onnes in 1911, many superconductors were discovered and the critical temperature rose year by year. More than 2000 superconducting materials had been discovered by 1975, and the critical temperature had reached 22.3 K with the discovery of Nb3Ge in 1973. After that, however, no higher critical temperature was...

Using the large-N limit of the t–J model and also allowing for phonons and the electron–phonon interaction, we study the isotope effect α for coupling constants appropriate for YB2C3Oy. We find that α has a minimum at optimal doping and increases strongly (slightly) towards the underdoped (overdoped) region. Using values for the electron–phonon interaction from the local density approximation w...

The investigations performed in this work primarily deal with the question whether or no phonon±plasmon coupling along the c-axis in metallic La2CuO4 will occur in case a realistic electronic bandstructure based on the local density approximation (LDA) is employed for the calculation of the electronic polarizability P and the dielectric matrix e. Phonon±plasmon mixing will appear in a significa...

This study presents synthesis results of catalysts made perovskite-like oxide La2-xSrxCuO4 (x=0.0, 0.5, 1.0) using the citrate method and crystallisation at 800°C. The structure was characterised by X-ray diffraction (XRD). catalyst activity enhanced with gold (Au) platinum (Pt). Au mounted on sol-gel method. perovskite LaMnO3/LaCuO3 evaluated complete oxidation volatile hydrocarbons (HCs) in a...

We develop the interface tool wan2respack, which connects RESPACK (software that derives low-energy effective Hamiltonians of solids) with Wannier90 constructs Wannier functions). wan2respack converts functions obtained by into those used in RESPACK, is then to derive solids. In this paper, we explain basic usage and show its application standard compounds correlated materials, namely, metal Sr...