Objetivo The low-temperature properties of semiconductors are determined by quantum coherent effects. However, recent studies of transport properties in the extreme quantum limit (EQL) and in highly disordered systems revealed new additional peculiarities which are not yet explained. The main aim of this project is to study the influence of common action of high magnetic field, especially extreme quantum limit, and strong disorder on quantum transport effects in 2D systems. The following peculiarities will be studied: quantum corrections to 2D conductivity in EQL but out of quantum Hall regime; quantum corrections to ultrasonic absorption; peculiarities of the QHE due to its competition with metal insulator transition (MIT); and finally the electron phase diagram in magnetic field. The quantum oscillations of intensity and velocity of surface acoustic waves are expected and will be studied in the regime of quantum Hall effect. In the insulating state the structure of upper Hubbard band will be studied under magnetic field action to reveal the nature of both giant and double-dip negative magnetoresistance. Measurements will be performed in various 2D and quasi-2D semiconducting structures such as strained and unstrained heterostructures, superlattices and delta-doped epitaxial layers based on GaAs/GaInAs, GaAs/GaInP, GaAs but mainly on the Ge-Si system. The Ge-Si system enables a wide range of tunable effective masses to be accessed making it a unique system for the study of 2D properties. Recent dramatic developments in Ge-Si technology have made this possible. This material system is very promising for the above investigations and has potential advantages in the study of Wigner crystallisation. All measurements will be combined with studies of random potential characteristics by various methods such as X-ray diffraction and reflectivity, transmission electron microscopy (TEM), cross-section transmission electron microscopy (XTEM), photoluminescence and field effect. It may provide the means to obtain new information on the role of disorder. Programa(s) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Tema(s) 15 - Condensed Matter Physics Convocatoria de propuestas Data not available Régimen de financiación Data not available Coordinador Centre National de la Recherche Scientifique Aportación de la UE Sin datos Dirección Avenue de Rangueil 31077 Toulouse Francia Ver en el mapa Coste total Sin datos Participantes (5) Ordenar alfabéticamente Ordenar por aportación de la UE Ampliar todo Contraer todo National Academy of Sciences of Ukraine Ucrania Aportación de la UE Sin datos Dirección 310085 Kharkov Ver en el mapa Coste total Sin datos Russian Academy of Sciences Rusia Aportación de la UE Sin datos Dirección 194021 St. Petersburg Ver en el mapa Coste total Sin datos Russian Research Centre I.V. Kurchatov Institute Rusia Aportación de la UE Sin datos Dirección 123182 Moscow Ver en el mapa Coste total Sin datos State University of Nizhny-Novgorod Rusia Aportación de la UE Sin datos Dirección 603600 Nizhny Novgorod Ver en el mapa Coste total Sin datos UNIVERSITY OF WARWICK Reino Unido Aportación de la UE Sin datos Dirección Gibbet Hill Road COVENTRY Ver en el mapa Enlaces Sitio web Opens in new window Coste total Sin datos