Festkörperprobleme 28: Plenary Lectures Of The 52nd Annual Meeting Of The German Physical Society (dpg) And Of The Divisions “semiconductor Physics” “dynamics And Statistical Physics” “thin Films” “surface Physics” “low Temperature Physics” “magnetism” “metal Physics” Karlsruhe, March 14…18, 1988

FESTKORPERPROBLEME ADVANCES IN SOLID STATE PHYSICS 28 FESTKORPER PROBLEME ADVANCES IN SOLID STATE PHYSICS 28 Plenary Lectures of the 52nd Annual Meeting of the German Physical Society (DPG) and of the Divisions "Semiconductor Physics" "Dynamics and Statistical Physics" "Thin Films" "Surface Physics" "Low Temperature Physics" "Magnetism" "Metal Physics" Karlsruhe, March 14... 18, 1988 Edited by U. RSssler, Regensburg With 110 Figures Friedr. Vieweg & Sohn Braunschweig / Wiesbaden Vieweg is a subsidiary company of the Bcrtelsmann Publishing Group. All rights reserved © Friedr. Vieweg & Solon VerlagsgeseIIschaft mbH, Braunschweig 1988 No part of this publication may be reproduced, stored in a retrieval system or transmitted, mechanical photocopyi.ag or otherwise, without prior permission or' the copyright holder. Set by Vicweg, Braunschweig Printed by Lcngcricher Handelsdruckerei, Lcngcrich Bound by W. Langeliiddccke, Braunschwcig Cover design: Barbara Scebohm, Braunschwcig ISSN ISBN 0430-3393 3-528-08034-5 Foreword The spring meeting 1988 o f the Solid State Physics Division (Arbeitskreis Festk6rperphysik) o f the Deutsche Physikalische Gesellschaft was held in Karlsruhe together with the 52nd Annual Plenary Conference of the society. A selection of plenary and invited talks o f this conference is published in this volume o f Advances in Solid State Physics/Festk6rperprobleme. It will become apparent from the contents, that this selection is not representative for the wide spectrum o f topics presented at the conference. But, unfortunately, several speakers who were invited to contribute to this volume, did not provide manuscripts because o f current or more recent publications in their respective fields, or because o f lack o f time. With the exception o f a review on the theory o f high-To-superconductors all contributions are devoted to current topics in semiconductor physics. This years winner of the Walter-Schottky Prize, M. Stutzmann, reports on his contributions to an understanding of the interrelation between electronic density o f states and structural relaxation in hydrogenated amorphous Silicon. Two articles report on magnetooptical and microwave investigations of the quantum-Hall effect. Theoretical aspects o f semiconductors under high excitation conditions, the fabrication o f the 4 Mega-bit random access memory, and the physics o f semiconductor microstructures under the aspects o f reduced dirnensionality complete the list o f topics. It is a pleasure to thank the authors for their contributions, and Bj6rn Gondesen (Vieweg-Verlag) for his cooperation. I express my gratitude to Peter Grosse, the former editor, for the work he did for the "Festk6rperprobleme" and for his advice and help, when I took over this job last fall. Regens, May 1988 Ulrich R6ssler V Contents Martin Stutzmann Charge-Induced Structural Relaxation in Hydrogenated Amorphous Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Igor Kukushkin, Vladislav Timofeev, Klaus v. Klitzing,Klaus Ploog Magnetooptics of Two-Dimensional Electrons Under the Conditions of Integral and Fractional Quantum Hall Effect in Si-MOSFETs and GaAs-AIGaAs Single Heterojunctions . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Friedl Kuchar Microwave Investigations of the Quantum Hall Effect in GaAs/AIGaAs Heterostructures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 WilfriedSchi,fer Recent Developments in the Theory of Highly Excited Semiconductors .... 63 The Development of a 4 Mbit DRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Wi