Abstract The recent and exciting discovery of superconductivity in the hole-doped infinite-layer nickelate Nd 1− δ Sr NiO 2 draws strong attention to correlated quantum materials. From a theoretical view point, this class unconventional superconducting materials provides an opportunity unveil physics hidden Here we study temperature doping dependence local spectrum as well charge, spin orbital ...

Electrical transport through a normal metal / superconductor contact at biases smaller than the energy gap can occur via the reflection of an electron as a hole of opposite wave vector. The same mechanism of electron-hole reflection gives rise to low energy states at the surface of unconventional superconductors having nodes in their order parameter. The occurrence of electron-hole reflections ...

The effect of hydrostatic pressure up to 2 GPa on the superconductiong transitions in La 2−x Sr x CuO 4+δ is investigated. The ambient and high pressure properties of two series of samples with x=0 and x=0.015 and 0< δ <0.1 are characterized and compared by ac-susceptibility measurements. At ambient pressure both sets of samples fit into the same phase diagram as a function of the total hole co...

We studied the optical conductivity of electron doped Pr1−xCexCuO4 from the underdoped to the overdoped regime. The observation of low to high frequency spectral weight transfer reveals the presence of a gap, except in the overdoped regime. A Drude peak at all temperatures shows the partial nature of this gap. The close proximity of the doping at which the gap vanishes to the antiferro-magnetic...

Abstract This experiment addressed the effect of Nickel-doped on dielectric, ac conductivity, and optical properties pure doped Zn (1−x) Ni x O (x = 0, 3 6%) nanostructures. The un-doped Ni-doped ZnO nanostructures were synthesized using co-precipitation. In this paper, frequency-dependent dielectric electrical conductivity examined at various temperatures ranging from 320 K to 460 an LCR meter...

We define a new type of spectrum, called δ-approximate spectrum, of an element a in a complex unital Banach algebra A and show that the δ-approximate spectrum σ_δ (a) of a is compact. The relation between the δ-approximate spectrum and the usual spectrum is investigated. Also an analogue of the classical Gleason-Kahane-Zelazko theorem is established: For each ε>0, there is δ>0 such that if ϕ is...