Advances In Research

SOLID STATE PHYSICS VOLUME 20 Contributors to This Volume R. Brill Robert W. Keyes Philip C. K. Kwok Takeo Nagamiya M. D. Sturge SOLID STATE PHYSICS Advances in Research and Applications Editors FREDERICK SEITZ Department of Physics, University of Illinois? Urbana, Illinois DAVID TURNBULL Division of Engineering and Applied Physics, Harvard University Cambridge,Massachusetts HENRY EHRENREICH Division of Engineering and Applied Physics, Harvard [Jniversity Cambridge,Massachusetts VOLUME 20 1967 @ ACADEMIC PRESS 0 NEW YORK AND LONDON COPYRIGHT @ 1967, BY ACADEMICPRESSINC. ALL RIQHTS RESERVED NO PART O F THIS BOOK MAY B E REPRODUCED IN ANY FORM, BY PHOTOSTAT, MICROFILM, OR ANY OTHER MEANS, WITHOUT WRITTEN PERMISSION FROM T E E PUBLISHERS. ACADEMIC PRESS INC. 111 Fifth Avenue, New York, New York 10003 United Kingdom Edition published by ACADEMIC PRESS INC. (LONDON) LTD. Berkeley Square House, London W.l LIBRARY OF CONGRESS CATALOG CARD NUMBER:55-12200 PRINTED I N THE UNITED STATES OF AMERICA Contributors to Volume 20 R. BRILL,Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin-Dahlem, Germany ROBERTW. KEYES,IBM Thomas J. Watson Research Center, Yorktown Heights, New York PHILIP C . K. KWOK,IBM Thomas J . Watson Research Center, Yorktown Heights, New York TAKEO NAGAMIYA,* Department of Material Physics, Faculty of Engineering Science, Osaka University, Toyonaka, Japan M. D. STURGE, Bell Telephone Laboratories, Incorporated, Murray Hill, New Jersey * Present Address : Physics Department, University of Arizona, Tucson, Arizona. V This Page Intentionally Left Blank Preface In the first article of this volume, Brill surveys concisely X-ray methods of determining electron spatial distributions in crystals and their application to the various solid types. I n Volume 11 of “Solid State Physics,” Keyes discussed the effect of strain on the band structure of semiconductors. In the present volume, he shows how electronic effects may modify the elastic properties of semiconductors. Although the Jahn-Teller effect was predicted thirty years ago, it is only recently that its manifestation in solids has been extensively explored. Sturge summarizes critically the results of this exploration from both the experimental and theoretical viewpoints. The article by Kwok presents for the first time in this serial publication a systematic exposition of the application of the Green’s function technique to solids. It is hoped that the present application to lattice vibrations and phonon-photon interactions will be followed by articles applying this technique to other phenomena. In the final contribution to this volume Nagamiya presents a molecular field treatment of the theory of spin ordering, with special emphasis on helical arrangements, and its application to the interpretation of experiment. In a future contribution Nagamiya plans to discuss the role of conduction electrons in the exchange interaction. FREDERICK SEITZ DAVIDTURNBULL HENRYEHRENREICH October, 1967 Vii This Page Intentionally Left Blank Contents CONTRIBUTORS TO VOLUME20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PREFACE ................................................................. CONTENTS OF PREVIOUS VOLUMES .......................................... SUPPLEMENTARY MONOGRAPHS ............................................. ARTICLESTO APPEAR SHORTLY ............................................. v vii xi xv xvi Determination of Electron Distribution in Crystals by Means of X Rays R . BRILL I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . .