Jožef Stefan Institute

About: Jožef Stefan Institute is a facility organization based out in Ljubljana, Slovenia. It is known for research contribution in the topics: Liquid crystal & Dielectric. The organization has 3828 authors who have published 12614 publications receiving 291025 citations.

Electronic correlations, magnetism, and Hund's rule coupling in the ruthenium perovskites SrRuO 3 and CaRuO 3

Abstract: A comparative density functional plus dynamical mean field theory study of the pseudocubic ruthenate materials ${\text{CaRuO}}_{3}$ and ${\text{SrRuO}}_{3}$ is presented. Phase diagrams are determined for both materials as a function of Hubbard repulsion $U$ and Hund's rule coupling $J$. Metallic and insulating phases are found, as are ferromagnetic and paramagnetic states. The locations of the relevant phase boundaries are determined. Based on the computed phase diagrams, Mott dominated and Hund's dominated regimes of strong correlation are distinguished. Comparison of calculated properties to experiments indicates that the actual materials are in the Hund's coupling dominated region of the phase diagram so can be characterized as Hund's metals, in common with other members of the ruthenate family. Comparison of the phase diagrams for the two materials reveals the role played by rotational and tilt $({\text{GdFeO}}_{3}$-type) distortions of the ideal perovskite structure. The presence of magnetism in ${\text{SrRuO}}_{3}$ and its absence in ${\text{CaRuO}}_{3}$ despite the larger mass and larger tilt/rotational distortion amplitude of ${\text{CaRuO}}_{3}$ can be understood in terms of density of states effects in the presence of strong Hund's coupling. Comparison of the calculated low-$T$ properties of ${\text{CaRuO}}_{3}$ to those of ${\text{SrRuO}}_{3}$ provides insight into the effects of magnetic order on the properties of a Hund's metal. The study provides a simultaneous description of magnetism and correlations and explicates the roles played by band theory and Hubbard and Hund's interactions.

Surface Analysis of 1-Hydroxybenzotriazole and Benzotriazole Adsorbed on Cu by X-Ray Photoelectron Spectroscopy

Abstract: The surface chemistry of two corrosion inhibitors, 1-hydroxybenzotriazole (BTAOH) and benzotriazole (BTAH), adsorbed on copper from 3% NaCl aqueous solution, was investigated by X-ray photoelectron spectroscopy (XPS). Surface and subsurface chemical structure, composition, and layer thickness were obtained from angle-resolved XPS measurements, from detailed analysis of the background in the XPS spectra by the Tougaard method, and from XPS depth profiling performed by Ar-ion sputtering. The main concern was the shape of the X-ray induced Auger Cu L 3 M 4,5 M 4,5 spectrum that offers the possibility to investigate the Cu(I) environment. The Auger Cu L 3 M 4,5 M 4,5 spectrum obtained after treatment in the BTAH-containing solution was decomposed into three components originating from the Cu(I)BTA complex layer, the Cu 2 O underlayer, and the Cu substrate. This procedure indicates the formation of the Cu(I)BTA surface complex on the Cu 2 O underlayer after BTAH treatment. The BTAH molecules [either in the Cu(I)BTA complex or uncomplexed] are directed toward the Cu surface through their triazole N atoms. In contrast to the BTAH treatment, the Cu-BTAOH layer formed on the Cu surface after treatment in the BTAOH solution is less ordered and is much thinner than the Cu-BTAH structure.

Aerial base stations with opportunistic links for next generation emergency communications

Abstract: Rapidly deployable and reliable mission-critical communication networks are fundamental requirements to guarantee the successful operations of public safety officers during disaster recovery and crisis management preparedness. The ABSOLUTE project focused on designing, prototyping, and demonstrating a high-capacity IP mobile data network with low latency and large coverage suitable for many forms of multimedia delivery including public safety scenarios. The ABSOLUTE project combines aerial, terrestrial, and satellites communication networks for providing a robust standalone system able to deliver resilience communication systems. This article focuses on describing the main outcomes of the ABSOLUTE project in terms of network and system architecture, regulations, and implementation of aerial base stations, portable land mobile units, satellite backhauling, S-MIM satellite messaging, and multimode user equipments.