Table Of ContentHandbook of Surface Science
Volume I
Handbook of Surface Science
Volume I
Handbook of Surface Science
Series editors
S. HOLLOWAY
Surface Science Research Centre
Liverpool, UK
N.V. RICHARDSON
Director, Surface Science Research Centre
Liverpool, UK
ELSEVIER
AMSTERDAM (cid:12)9 LAUSANNE (cid:12)9 NEW YORK (cid:12)9 OXFORD (cid:12)9 SHANNON (cid:12)9 TOKYO
Volume I
Physical Structure
Volume editor
W.N. UNERTL
Laboratory for Surface Science and Technology
Sawyer Research Center
University of Maine
Orono, ME 04469
USA
1996
ELSEVIER
AMSTERDAM (cid:12)9 LAUSANNE (cid:12)9 NEW YORK * OXFORD (cid:12)9 SHANNON (cid:12)9 TOKYO
ELSEVIER SCIENCE B.V.
Sara Burgerhartstraat 25
P.O. Box 211, 1000 AE Amsterdam, The Netherlands
Llbrary oF Congress Cataloging-In-Publication Data
Physical structure / volume editor, W.N. Unertl.
p. cm. -- (Handbook of surface science ;v. 1)
Includes bibliographical references and indexes.
ISBN 0-444-89036-X
1. Solids--Surfaces. 2. Surfaces (Physics) 3. Surface chemistry.
4. Energy-band theory of solids. I. Unertl, W. N. (William N.)
II. Series
QC176.8.S8P49 1996
530.4'17--dc21 96-44174
CIP
ISBN 0-444-89036-X (Volume 1)
ISBN 0-444-82526-6 (Series)
(cid:14)9 1996 Elsevier Science B.V. All rights reserved.
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Printed in The Netherlands.
General Preface
How many times has it been said that surface science has come of age? Rather than
being a fledgling area of study, it is now patently clear that the investigation of solid
surfaces and related interfacial problems is a unique field with profound implications
for basic (dare one say academic!) scientific study and the understanding of materials.
Surface science provides major support to many technologically ambitious industries.
It is widely recognised that it underpins the fabrication of electronic devices but this
also extends to any industry working in nanotechnology. Surface science makes
significant contributions to product development and problem solving in many mate-
rials-based industries where surface finish, cleanliness, adhesion, wear or friction are
important. An understanding of surface processes is vital in chemical industries
because of the importance of heterogeneous catalysis and is likely to make major
contributions to the growing optoelectronics and molecular sensing industries. In
social terms, an improved understanding of surfaces will facilitate the development
of better catalysts and sensors for improvement of our environment.
In this series, we have brought together some of the key players that have made
seminal contributions to the study of solid surfaces and their interactions with
foreign species. Because of the broad scope of surface science, even when restricted
to the solid surfaces which we hope to cover in this series, we have been coerced
into 'packaging' the subject in what is, it must be said, a rather arbitrary way. No
doubt different editors would have chosen different themes around which to base
individual volumes.
This first volume is devoted to determining, by measurement and calculation the
geometry of the surface. This is probably the oldest field of surface science
investigation, dating back to the original experiments of Davisson and Germer
employing electrons, and Estermann and Stern using atomic He beams to determine
the crystal lattice constants in the surface region. In Volume 1, a wide variety of
contemporary techniques are presented that now enable one to determine the
location of atoms in the substrate surface as well as those in adsorbed molecules.
This has enabled investigators to shed light on such issues as, how molecules can
deform in the adsorbed state, and, the role of genuine surface relaxations both for
a clean surface as well as for one covered by foreign species. The contributions deal
with a wide variety of surface types, metals, insulators, ceramics etc. all of which
play a role in real-world technological applications.
Volume 2 deals with the determination of the electronic properties of surfaces.
As previously acknowledged, the separation is arbitrary and it is accepted that once
it is known where the electrons are, then by calculating the total energy of the
system, the geometry is uniquely determined simply by minimization. Well, these
are early days and, while we believe that within the next decade this procedure will
(hopefully) be routine, the electronic spectroscopies applied to surfaces and inter-
faces form a section of their own and are reviewed in depth in Volume 2.
Volume 3 will address the dynamical aspects of surfaces and surface processes,
reflecting in detail current understanding of energy exchange at surfaces and the
part this plays in the adsorption and reaction of atoms and molecules at surfaces.
Surface dynamics is, of course, intimately related to the geometric and electronic
properties of the surface and while Volumes 1 and 2 address the equilibrium
geometry and ground state electronic properties, Volume 3 pays particular attention
to the response of surfaces to external stimulation.
Taken as a set, the three volumes of this series aim to provide an in-depth
introduction to the world of surface and interfacial science and would be most
suited for scientists having obtained a first degree in the natural sciences.
N. V. Richardson and S. Holloway
Surface Science Research Centre
Liverpool, UK
Preface to Volume 1
The primary goal of this book is to summarize the current level of accumulated
knowledge about the physical structure of solid surfaces with emphasis on well-de-
fined surfaces at the gas-solid and vacuum-solid interfaces. The intention is not
only to provide a standard reference for practitioners, but also to provide a good
starting point for scientists who are just entering the field. Thus, the presentation in
most of the chapters assumes that the typical reader will have a good undergraduate
background in chemistry, physics, or materials science but little, or no, knowledge
of surface science. At the same time, coverage is comprehensive and at a high
technical level with emphasis on fundamental physical principles.
It is appropriate that this first volume of the Handbook of Surface Science is
devoted to the physical structure of surfaces since knowledge of the atomic posi-
tions is often essential for complete understanding of electronic properties or
dynamical processes that are the topics of the following two volumes.
This volume is divided into four parts. Part I describes the equilibrium proper-
ties of surfaces with emphasis on clean surfaces of bulk materials. Chapter 1 defines
the terminology and notations used to describe the crystallography of surfaces of
crystals. Chapter 2 then outlines the relationships between the atomic structures and
the macroscopic thermodynamic properties of surfaces. The major theoretical
approaches that are used to calculate the structure of surfaces are presented and
critiqued in Chapters 3 and 4. Chapter 3 emphasizes metals and elemental semicon-
ductors and Chapter 4 emphasizes insulators. Chapters 5 and 6 are devoted to
crystalline ceramics and to elemental and compound semiconductors, respectively.
They demonstrate the complexity that can occur in multicomponent materials.
Part II provides an introduction to some of the primary experimental methods
that are used to determine surface crystal structures. Chapter 7 covers the three main
diffraction methods. Chapter 8 describes techniques that provide more direct im-
ages. Spectroscopic techniques will be covered in a future volume of this Hand-
book.
Part III provides an overview of the vast topic of the structure of adsorbed layers.
A systematic treatment of the rich variety of structures formed by chemically
adsorbed species is given in Chapter 9. Chapter 10 is an in-depth treatment of the
structures that occur in physically adsorbed layers. Chapter 11 covers the complex
topic of theoretical prediction of the interactions between adsorbed atoms.
vii
Part IV concludes the book. Chapter 12 covers the important topic of defects in
surface structures. Chapter 13 is a comprehensive treatment of phase transitions that
covers aspects of structure that go beyond local interactions.
Surface science is a broad and interdisciplinary subject. This volume should be
viewed as a general introduction rather than a comprehensive treatment. Nearly
every chapter could easily be expanded into a full volume. Thus, some specific
topics that are closely related to surface structure, such as surface magnetism and
surface lattice dynamics, have not been included. Look for these in future volumes
of the Handbook of Surface Science.
I want to express my thanks to the Handbook editors and the publisher for
offering me the opportunity to organize this volume. I am especially grateful to
Patricia Paul and Barbara Deshane for their assistance in bringing this project to
completion.
William N. Unertl
Orono, ME, USA
viii
Contents of Volume 1
General Preface ................................... iv
Preface to Volume 1 ................................. vii
Contents of Volume 1 ................................ ix
Contributors to Volume 1 .............................. xi
List of Symbols and Acronyms ........................... xiii
Part L Basic aspects of the structure of crystalline surfaces
1. W.N. Unertl
Surface crystallography ............................. 3
2. E.D. Williams and N.C. Bartelt
Thermodynamics and statistical mechanics of surfaces ............ 51
3. C.T. Chan, K.M. Ho and K.P. Bohnen
Surface reconstruction: metal surfaces and metal on semiconductor
surfaces .................................... 101
4. J.P. LaFemina
Theory of insulator surface structures .................... 137
5. R.J. Lad
Surface structure of crystalline ceramics ................... 185
6. C.B. Duke
Surface structures of elemental and compound semiconductors ....... 229
Part IL Experimental methods to study surface structure
7. E.H. Conrad
Diffraction methods .............................. 271
8. W.N. Unertl and M.E. Kordesch
Direct imaging and geometrical methods .................. 361
Part III. Structure of adsorbed layers
9. H. Over and S.Y. Tong
Chemically adsorbed layers on metal and semiconductor surfaces ..... 425
ix
