Advantages of Ferroelectrics as a Component of Heterostructures for Electronic Purposes: A DFT Insight.

The main advantage of using ferroelectric materials as a component of complex heterostructures is the ability to tune various properties of the whole system by means of an external electric field. In particular, the electric field may change the polarization direction within the ferroelectric material and consequently affect the structural properties, which in turn affects the electronic and magnetic properties of the neighboring material. In addition, ferroelectrics allow the electrostriction phenomenon to proceed, which is promising and can be used to affect the magnetic states of the interface state in the heterostructure through a magnetic component.

DFT Insight into Conductive and Magnetic Properties of Heterostructures with BaTiO Overlayer.

The ab initio calculations of a heterostructure based on the ferroelectric phase of barium titanate and dielectrics lanthanum manganese (LaMnO) or silicon (Si) are presented. We analyze structures of BaTiO/LaMnO and BaTiO/Si interfaces, investigate magnetic properties and the impact of ferroelectric polarization. The use of ferroelectrics in the heterostructure plays a crucial role; in particular, ferroelectric polarization leads to the appearance of the conducting state at the interface and in the layers close to it.

Origin of Negative Photoconductivity at the Interface of BaSrTiO/LaMnO/BaSrTiO Heterostructures.

The study of BaSrTiO/LaMnO/BaSrTiO heterostructures on a MgO substrate with BaSrTiO ferroelectric films revealed the occurrence of a metallic character of the temperature behavior of the resistance at a temperature less than 175 K. This behavior is associated with an increased charge concentration at the interface due to a discontinuity in the ferroelectric polarization at the interface between the films. At these temperatures, the effect of negative photoconductivity is observed under uniform illumination with the light of a selected spectral composition event on the surface of the ferroelectric film.

Fabrication of High-Temperature Quasi-Two-Dimensional Superconductors at the Interface of a Ferroelectric Ba_{0.8}Sr_{0.2}TiO_{3} Film and an Insulating Parent Compound of La_{2}CuO_{4}.

We report the first observation of superconductivity in a heterostructure consisting of an insulating ferroelectric film (Ba_{0.8}Sr_{0.2}TiO_{3}) grown on an insulating parent compound of La_{2}CuO_{4} with [001] orientation.

Effect of national HIV testing recommendations and local interventions on HIV testing practices in a Swiss university hospital: a retrospective analysis between 2012 and 2015.

Objectives: Despite HIV testing recommendations published by the Federal Office of Public Health (FOPH) since 2007, many individuals living with HIV are diagnosed late in Switzerland. The aim of this study is to examine the effect of the 2013 FOPH HIV testing recommendations on HIV testing rates.

Setting: Ten clinical services at Lausanne University Hospital, Lausanne, Switzerland.