Fyzikální ústav Akademie věd ČR

In the solid-state field the research is aimed at new forms of solids, new physical phenomena and principles of microelectronic components. The properties of new materials are determined by surface, defects, nanometric, layered or aperiodic structures. The research of solids is characterized by a fusion of advanced technologies for preparing novel materials, cutting-edge methods for their characterization in a wide range of external conditions down to nanometric as well as atomic levels and the discussion of results using microphysical and ab-initio theoretical calculations. The main focus is put on magnetically and optically active materials, nanocrystalline forms of silicon, III-V semiconductors, diamond and graphite, and nanostructures for biologic, medical and microelectronic applications.

To begin with, systems of the so-called quantum dots, utilizable for a wide scale of optoelectronic applications such as novel types of lasers and detectors, are prepared using Metal-Organic Chemical Vapour Deposition (MOCVD). In addition, dilute ferromagnetic semiconductors based on GaMnAs, which seem to be suitable e.g. for the construction of next-generation fieldeffect transistors in the emerging field of the so-called spin electronics (spintronics), are produced by Molecular Beam Epitaxy (MBE). In the preparation of these materials, record high temperatures were reached at which the components made from them still operate.

Moreover, structural analysis especially of materials with disturbed translational symmetry using a unique JANA program is carried out by X-ray, electron and neutron diffraction. This analysis yields not only the positions of atoms in the crystal and their modulation but also the information about the occurrence of domains and the arrangement of magnetic moments, which are obtained from X-ray spectroscopy as well. The knowledge of the structure of materials is closely related to the first-principles calculations of their hardness. Novel hybrid magnetic nanoparticles, which may be used in diagnostics as well as in magnetic fluid hyperthermia, are developed; research is carried out on selected magnetic materials under extreme conditions, at high pressures, low temperatures, and in high magnetic fields. Thermally stable thermo-electric materials for the conversion of thermal into electrical energy are studied experimentally. Theoretical calculations involve both the study of electron structure and the numerical simulations of magnetic materials and substances with strong electron correlation.

Last but not least, Plasma-Enhanced Chemical Vapour Deposition (PECVD) is utilized for the preparation of nanocrystalline Si suitable for photovoltaic cells; Si nanocrystals are also studied for a theoretically predicted silicon laser. Unique results have been achieved in the targeted manipulation of individual atoms. Various forms of nanodiamonds prepared by the microwave PECVD technique, particularly promising for bio-applications, are studied intensely. A remarkable effect, namely unconventional superconductivity, has been discovered in this material and is studied both experimentally and theoretically. The preparation and characterization of new scintillation materials are among traditional research branches closely linked to the CERN laboratories and the Czech industry.