Obiettivo 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. Programma(i) IC-INTAS - International Association for the promotion of cooperation with scientists from the independent states of the former Soviet Union (INTAS), 1993- Argomento(i) 15 - Condensed Matter Physics Invito a presentare proposte Data not available Meccanismo di finanziamento Data not available Coordinatore Centre National de la Recherche Scientifique Contributo UE Nessun dato Indirizzo Avenue de Rangueil 31077 Toulouse Francia Mostra sulla mappa Costo totale Nessun dato Partecipanti (5) Classifica in ordine alfabetico Classifica per Contributo UE Espandi tutto Riduci tutto National Academy of Sciences of Ukraine Ucraina Contributo UE Nessun dato Indirizzo 310085 Kharkov Mostra sulla mappa Costo totale Nessun dato Russian Academy of Sciences Russia Contributo UE Nessun dato Indirizzo 194021 St. Petersburg Mostra sulla mappa Costo totale Nessun dato Russian Research Centre I.V. Kurchatov Institute Russia Contributo UE Nessun dato Indirizzo 123182 Moscow Mostra sulla mappa Costo totale Nessun dato State University of Nizhny-Novgorod Russia Contributo UE Nessun dato Indirizzo 603600 Nizhny Novgorod Mostra sulla mappa Costo totale Nessun dato UNIVERSITY OF WARWICK Regno Unito Contributo UE Nessun dato Indirizzo Gibbet Hill Road COVENTRY Mostra sulla mappa Collegamenti Sito web Opens in new window Costo totale Nessun dato
