Institution: | a Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland b Semiconductor Physics Institute, A. Gostauto 11, LT-01108 Vilnius, Lithuania c Hamburger Synchrotronstrahlungslabor HASYLAB am Deutschen Elektronen-Synchrotron DESY, Notkestr. 85, D-22603 Hamburg, Germany |