Graduate Texts in Contemporary Physics

Editor-in-Chief Jeffrey W. Lynn

Based on Lectures at the University of Maryland

College Park

(University of Maryland, College Park)

Editorial Board (At the University of Maryland, College Park)

Alex J. Dragt Richard A. Ferrell Oscar W. Greenberg Richard E. Prange Philip G. Roos Guarang Y odh

Graduate Texts in Contemporary Physics

R.N. Mohapatra: Unification and Supersymmetry: The Frontiers of Quark-Lepton Physics

R.E. Prange and S.M. Girvin (eds.): The Quantum Hall Effect, 2nd ed.

M. Kaku: Introduction to Superstrings

J.W. Lynn (ed.): High Temperature Superconductivity

H.Y. Klapdor(ed.): Neutrinos

J.H. Hinken: Superconductor Electronics: Fundamentals and Microwave Applications

High Temperature Superconducti vity

Edited by Jeffrey W Lynn

With Contributions by Philip B. Allen, Femand D. Bedard, Dietrich Belitz, Jack E. Crow, Richard A. Ferrell, Jeffrey W. Lynn, Nai-Phuan Ong, Anthony Santoro, Robert N. Shelton, and Ching-ping S. Wang

With 125 Illustrations

Springer-Verlag New York Berlin Heidelberg London Paris Tokyo Hong Kong

Jeffrey W. Lynn Center for Superconductivity Research Department of Physics University of Maryland College Park, MD 20742-4 11 1, USA

Library of Congress Catatnging· in·Publication Data Higb temperature superconductivity 11effrey W. Lynn, editor.

p. cm. - (Graduate texts in contemporary physics) Includes bibliographical references. ISBN·13: 978·1-4612·7921-1 I. High temperature superconductivity. L Lynn. Jeffrey W.

II . Series. QC611.98. H.')4H~33 1990 .')37.6'23-dc20 90·9436

Printed on acid-free paper.

C 1990 by Springer-Verlag New York Inc. Soflcovcr reprint of the hardcover h t edition 1990

All rights reserved. This work may not Ix: translated or copied in whole or in pall without the written permission of the publisher (Springer-Verlag, 175 Fifth Avenue, New York. NY 10010. USA). eltcept for brief Cltccrpts in connection with reviews or scholarly analysis . Use in connec­tion with any form of information StOrage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of general descriptive names, trade names. trade marks, etc. in this publication, even if the fonner are nO( especially identified. is not to be taken as a sign that such names. as under­stood by the Trade Marks and Merchandise Marks Act. may accordingly Ix: used freely by anyone.

Camera-ready text provided by the editor.

9 8 7 6 .') 4 3 2 I

ISBN-13: 918-1-4612-7921- 1 e-ISBN-I3: 918-1-4612-3222-3 DOl: 10.10011978-1-4612-3222-3

To

The Memory of Captain Robert C. Mayo, USN

and

My Gorgeous Mother-In-Law

Preface

One of the most exciting developments in modem physics has been the discovery of the new class of oxide materials which have high superconducting transition temperatures. Systems with T c well above liquid nitrogen temperature are already a reality, and there is evidence for new materials with higher Tc's yet. Indeed, the science fiction allusion of a room-temperature superconducting system, which just a short time ago was considered ludicrous, appears today to be a distinct possible outcome of materials physics research.

These materials are interesting for two basic reasons. First, they present exciting new physics. A large variety of experimental techniques are being employed to investigate these materials, yet the physical mechanism responsible for the high Tc's has not been identified. Speculation, though, is rampant. The basic physics of these systems is being explored, and the level of effort is immense. The phenomenal popular interest, on the other hand, stems from the enormous potential of these materials for practical applications. A number of devices have already been fabricated, which make it clear that oxide superconductors could have a substantial economic impact. They are also intrinsically capable of supporting large critical currents, and if high-current devices can be successfully developed, then these new materials should have a diversity of applications. Nature, however, has been reluctant in revealing her secrets, and the road to economic success is a difficult one. On the optimistic side, though, it is clear that if room-temperature superconductivity ever becomes a reality, then superconductivity will have a profound influence on our everyday lives which could rival developments such as the transistor and the laser.

For both of the above reasons, a large number of scientists,

viii Preface

engineers, and technicians are being thrust into the field of superconductivity. To address the need for an advanced course on superconductivity, we arranged a graduate-level course at the University of Maryland in the Fall of 87. The purpose of the lectures was to reach graduate students as well as the many researchers at the University and in the surrounding Washington area. It was quite difficult to rmd an appropriate text for such a course, since there are very few books on superconductivity which are presently in print, and most of these are out-of-date and/or inappropriate as a general text on oxide superconductivity. We therefore decided to undertake the production of an up-to-date introduction to superconductivity, written in the style of a textbook, and then a set of chapters on the new high Tc materials. A series of introductory lectures was given at the beginning of the course, and then experts in the field of superconductivity were invited to present an extended lecture, and follow up with a written chapter. The result is the present book.

The first chapter is quite basic. However, for the beginner I would recommend rust reading an introduction to superconductivity such as is found in solid state texts like Kittel or Ashcroft and Mermin. Of course, it may be skipped by the more advanced reader. The next two chapters review the essential properties of .. conventional" superconductors: Chapter 2 is devoted to the theory of type-II superconductors, since the new oxides are all strong type-II materials, and Chapter 3 discusses the Josephson effect both because of the interesting quantum physics aspect as well as the important applications that derive from this effect.

Chapters 4-9 are devoted to the properties of the oxide superconductors, and are a mix of experiment and theory. Chapter 10 gives an overview of applications. These have been very difficult chapters to write because of the enormous volume of literature already available, because of the incredible pace of work presently under way worldwide, and because of the pressing needs of our own research programs. With a tutorial text in mind, we found it rather impossible to cite all the relevant articles: The citations alone could easily have filled the approximately 400 page limit. There are quite a number of conference proceedings which are already available, and there will be many more to come, and more extensive references can be found there. Nevertheless, we would like to apologize in advance for any work which may have been overlooked during the preparation of the present chapters.

I would like to thank my coauthors for the excellent lectures they presented, and for their assistance and encouragement during the preparation of these chapters. I would also like to thank Victor Korenman for his critical reading of the rust chapter, and Richard Prange for his verbal and compensatory encouragement.

Preface ix

Finally, I would like to thank Cay Horstmann, who was very helpful in his assistance with the word processing program which produced this book. All the chapters were produced using ChiWriter (Horstmann Software). I would also like to thank Julian Noble (Noble House Software) for his assistance with the program that produced the index (lndexchi).

College Park Jeffrey W. Lynn

Contents

Contributors

Chapter 1 Survey of Superconductivity Jeffrey W. Lynn 1.1. Introduction . . . . . . 1.2. dc Electrical Resistance 1.3. Perfect Diamagnetism .. 1.4. Energy Gap ...... . 1.5. Electron-Phonon Interaction and Cooper Pairing. 1.6. BCS Theory .......... . 1.7. Type-II Superconductors . . . . 1.8. New Topics in Superconductivity

References. . . . . . . . . . .

Chapter 2 Theory of Type-n Superconductivity Dietrich Belitz 2.1. Introduction . . . . . . 2.2. Ginzburg-Landau Theory. . . 2.3. Microscopic Theory ..... 2.4. Beyond Dirty Limit Theory .

References . . . . . . . . .

Chapter 3 The Josephson Effect Richard A. Ferrell 3.1. Phenomenology. 3.2. Microscopic Theory ........ .

xvii

1 1 2 4

11 12 16 19 22 27

29 29 32 40 48 57

60 60 71

xii Contents

3.3. Quantum Effects 79 3.4. Summary. . 81

References. . . 82

Chapter 4 Crystallography Anthony Santoro 84 4.1. Introduction . . . . . . . . 84 4.2. The Rietveld Method . . . . 86 4.3. The Structure of Perovskite 91 4.4. The System BaPbl_xBixOj. . 93 4.5. The System La2_xMxCU04_y (M = Ba, Sr) 97 4.6. The System Ba2MCu]Oo (M = Y, Gd, Eu, etc.) . 105 4.7. The System Ba2-xLal-xCu]Oo' . . . . . 113 4.8. The System BiCaSr2Cu~O' . . . . . . 115 4.9. Materials With Crystallographic Shear 118

References. . . . . . . . . . . . . . 118

Chapter 5 Electronic Structure, Lattice Dynamics, and Magnetic Interactions Ching-ping S. Wang 122 5.1. Introduction . . . . . . . . . . . . . . . 122 5.2. Electronic Structure of La2_x(Ba,Sr)xCu04 124 5.3. Electronic Properties of YBa2Cu]07-x . . . 132 5.4. Electronic Structure of the Bismuth and Thallium

Superconductors . . . . . . . 137 5.5. Electron-Phonon Interaction 144 5.6. Electron-Electron Correlations 148

References. . . . . . . . . . 161

Chapter 6 Synthesis and Diamagnetic Properties Robert N. Shelton 168 6.1. Introduction . . . . . . . . . . . . . . . . 168 6.2. The System La2_xMxCU04_y (M = Ba, Sr, Ca). 169 6.3. The System MBa2Cu]Ox (M = Rare Earth). 177 6.4. Superconductivity above 100 K 190

References. . . . . . . . . . . . . . . 192

Contents xiii

Chapter 7 Thermal and Transport Properties Jack E. Crow and 203

Nai-Phuan Ong 7.1. Introduction . . . . . . . . . . . . . . . . . . . 203 7.2. Normal State Transport Properties of the High-Te Oxides 204 7.3. Specific Heat 216 7.4. The Role of Phonons . 239

References . . . . . . 255

Chapter 8 Magnetic Properties Jeffrey W. Lynn 8.1. Introduction . . . . . 8.2. Cu-O Magnetism . . . 8.3. Rare Earth Magnetism.

References . . . . . .

Chapter 9

268 268 269 290 296

Electron Pairing: How and Wby? Philip B. Allen 303 9.1. Introduction 303 9.2. Cooper Pairs . . . 306 9.3. Bose Condensation. 309 9.4. BCS Theory for Te. 311 9.5. The Interaction in BCS Theory. 315 9.6. The BCS Ground State. . . . . 319 9.7. Off-Diagonal Long Range Order (ODLRO) 320 9.8. Eliashberg Theory of Electron-Phonon Superconductors 322 9.9. Excitons and Plasmons. . . . 324 9.10. Spin Fluctuations . . . . . . 327 9.11. Weak versus Strong Coupling. 328 9.12. Bipolarons . . . . . . . . . 329 9.13. The Hubbard Model in Strong Coupling. 331 9.14. RVB Theory. . . . . . . . . . 334 9.15. Oxygen Holes and Copper Spins. 335 9.16. Postscript 338

References . . . . . . . . . . 339

Chapter 10 Superconducting Devices Fernand D. Bedard 343 10.1. Introduction 343 10.2 Cryotron..... 344 10.3 Josephson Device . 353 10.4 A Voltage Standard 359 10.5 Single-Junction SQUID. 363

xiv

10.6 SQUID Magnetometer . 10.7 Two-Junction SQUIDs . 10.8 Binary Counter . . . . 10.9 Sampling Oscilloscope . 10.10 Transmission Lines 10.11. Conclusion

References . . .

Chemical Formula Index

Subject Index . . . . .

Contents

366 369 373 375 378 383 384

387

390

Contributors

Philip B. Allen Department of Physics State University of New York Stony Brook, NY 11794

Fe17UJnd D. Bedard Department of Defense Fort Meade, MD 20755

Dietrich Belitz Department of Physics, and Materials Science Institute University of Oregon Eugene, OR 97403

Jack E. Crow Physics Department Temple University Philadelphia, PA 19122

Richard A. Ferrell Center for Superconductivity

Research Department of Physics Universtiy of Maryland College Park, MD 20742

Jeffrey W. Lynn Center for Superconductivity Research Department of Physics University of Maryland College Park, MD 20742

Nai-Phuan Ong Department of Physics Princeton University Princeton, Nl 08544

Anthony Santoro Reactor Division National Institute of Standards

and Technology Gaithersburg, MD 20899

Robert N. Shelton Department of Physics University of California-Davis Davis, CA 95616

Ching-ping S. Wang Center for Superconductivity Research Department of Physics University of Maryland College Park, MD 20742