Dynamical Phenomena at Surfaces, Interfaces and Superlattices : Proceedings of an International Summer School at the Ettore Majorana Centre, Erice, Italy, July 1-13, 1984

This volume contains summaries of lectures and contributed papers delivered at an International Summer School on "Dynamical Phenomena at Surfaces, I nterfaces and Superl atti ces" hel d at the Ettore Maj orana Centre for Sci en­ tific Culture, Erice (Sicily), Italy, July 1-13, 1984. The School was orga­ ni zed under the auspi ces of the Surfaces and Interfaces Secti on of the Condensed Matter Division of the European Physical Society as the sixth course in the series on Materials Science and Technology. Approximately 60 parti c i pants from all regi ons of Europe, the Uni ted States, and further afield - Hong Kong, China, India - were able to take part in a program of 45 lectures and 11 contributed talks, which covered most of the solid-state aspects of the subject. In recent years, there has been an explosion of interest in the proper­ ties of carefully prepared surfaces, interfaces, and multilayer thin films. This advance in research has received its impetus from the technological re­ levance of surfaces and interfacial phenomena associated with heterogeneous catalysis, corrosion, and, particularly, new developments in microelectronics. One of the most important developments to emerge over the past decade has been our ability to prepare ultra-thin structures at the submicron level, i. e. , to engineer low-dimensional solids at the atomic-scale level.

I Structure.- 1. Structural Determination of Surfaces and Overlayers with Diffraction Methods (With 7 Figures).- 1.1 Introduction.- 1.2 Surface Diffraction Kinematics.- 1.3 Low-Energy Electron Diffraction (LEED).- 1.4 Reflection High-Energy Electron Diffraction (RHEED).- 1.5 Photoelectron Diffraction.- 1.6 Glancing Incidence X-Ray Diffraction.- 1.7 Atomic-Beam Diffraction.- References.- 2. Defects at Surfaces (With 17 Figures).- 2.1 Introduction.- 2.2 Systematic Description of Defects.- 2.3 Experimental Techniques.- 2.4 Schematic Description of Quantitative Evaluation.- 2.5 The Kinematic Approximation and Inclusion of Dynamic Effects.- 2.6 Instrumental Limitations.- 2.7 Examples.- 2.8 Conclusion.- References.- 3. Metal-Metal Superlattices (With 11 Figures).- 3.1 Introduction to Metal-Metal Superlattices.- 3.2 Preparation of Metallic Superlattices by Sputtering.- 3.3 Characterization.- 3.3.1 Rutherford Backscattering Spectroscopy (RBS).- 3.3.2 X-Ray Diffraction.- 3.3.3 Auger Electron Spectroscopy (AES).- 3.4 Summary.- References.- 4. Advances in Semiconductor Superlattices, Quantum Wells and Heterostructures.- 4.1 Superlattice Band Model and Experiment (1969–1972).- 4.2 Multibarrier Tunneling and Quantum Wells: Theory and Experiment (1973–1974).- 4.3 Optical Absorption for Quantum Wells and Superlattices (1974–1975).- 4.4 Raman Scattering (1976–1980).- 4.5 Modulation Doping (1978) and Subsequent Developments.- 4.6 Quantized Hall Effect (1980–1981) and Discovery of Fractional Filling (1982).- 4.7 Variety of Heterojunctions and Superlattices and Relevant Topics.- 4.8 In As-GaSb Superlattices (1977–1982) and Quantum Wells (1982-).- References.- Contributions.- Electronic Surface Transitions in Si(111)2 ×1 Studied by Polarized Light (With 2 Figures).- Short Range Bonding Interaction at Metal-Metal Interfaces (With 2 Figures).- II Lattice Dynamics.- 5. Phonons at Interfaces and Superlattices (With 8 Figures).- 5.1 Introduction.- 5.2 Interface Lattice Dynamics.- 5.3 Dynamics of Superlattices.- 5.3.1 Compositional Superlattices.- 5.3.2 Doping Superlattices.- References.- 6. Pseudopotentials and Dynamical Properties of Metallic Surfaces (With 3 Figures).- 6.1 Introduction.- 6.2 Total Energy.- 6.2.1 Bulk Case.- 6.2.2 Surface Case.- 6.3 Determination of the Selfconsistent Potential.- 6.4 Dynamical Matrix.- 6.5 Applications.- 6.6 Conclusions.- References.- 7. One-Phonon Scattering of He Atoms from the Ag (111) Surface (With 6 Figures).- 7.1 Introduction.- 7.2 DWBA Cross-Section.- 7.3 Atom-Surface Potential.- 7.4 Calculation for the (111) Surface.- References.- 8. Electron Energy-Loss Spectroscopy for Metal Surfaces (With 9 Figures).- 8.1 Introduction.- 8.2 Dipole Scattering.- 8.2.1 Dipole EELS in Nickel (111).- 8.2.2 Dipole EELS in Nickel (001).- 8.3 Impact Scattering.- References.- 9. Electron Energy-Loss Spectroscopy of Surfaces and Absorbates (With 5 Figures).- 9.1 Introduction.- 9.2 Electron Energy-Loss Spectroscopy.- 9.3 Application to Oxidation Processes.- 9.4 Bonding of Hydrocarbons on Transition Metals.- 9.5 Surface Phonons.- References.- Contributions.- High Resolution Inelastic He-Atom Scattering from Crystal Surfaces (With 3 Figures).- Surface Lattice Dynamics of Ordered Overlayers on Metals.- Bulk and Surface Phonons in Superlattices.- III Phase Transitions.- 10. Surface Reconstruction Phase Transformations (With 17 Figures).- 10.1 Introduction.- 10.2 Landau Theory of Structural Phase Transformations.- 10.2.1 Order-Disorder Transitions at Surfaces: Critical Exponents.- 10.2.2 Classification of the Au(110)(2 ×l) Order-Disorder Transition.- 10.2.3 Leed Spot-Profile Analysis of Au(110) (2 ×l) Phase Transition.- 10.2.4 X-Y Model with Cubic Anisotropy W(100)(?2×?2).- 10.3 Landau Theory of Incommensurate Surface Phases.- 10.3.1 ‘Soliton Superlattice’ Structure of Incommensurate Phase.- 10.3.2 Incommensurate Phase Fluctuations.- 10.4 Related Systems.- 10.4.1 Au, Ir, pt(100) and Au (111) Reconstructed Surfaces.- 10.4.2 Semiconductor Reconstructed Surfaces.- References.- 11. Structural Phase Transitions on W and Mo Surfaces (With 1 Figure).- 11.1 Introduction.- 11.2 Driving Mechanisms for the Structural Transition.- 11.3 Monte-Carlo Simulations of Model Two-Dimensional Hamiltonian.- 11.4 Effect of Adsorbate on the Transition.- 11.5 Soliton Picture for the Commensurate-Incommensurate Transition.- References.- Contributions.- Charge Density Waves in Layered Compounds (With 2 Figures).- Dynamics of Mismatched Overlayers (With 1 Figure).- IV Electronic States.- 12. Electronic Structure of Surfaces, Interfaces, and Superlattices.- 12.1 Introduction.- 12.2 Surfaces and Overlayers.- 12.2.1 Introduction.- 12.2.2 Local-Spin-Density-Functional (LSDF) Theory.- 12.2.3 Methodology and Approach.- 12.2.4 Surface and Interface Magnetism.- 12.2.4.1 Magnetism of Ni (OOl) and Fe (OOl).- 12.2.4.2 Interface Magnetism of Ag/Fe(001).- 12.2.4.3 Magnetism of the Ni/Cu Interface.- 12.2.5 Surface Multilayer Relexation: W(001).- 12.3 Metallic Superlattices.- 12.3.1 Introduction.- 12.3.2 Theoretical Approach.- 12.3.3 Results for NiCu and PdAu.- 12.3.3.1 CuNi.- 12.3.3.2 PdAu.- References.- 13. Electrons and Phonons in One and Two Dimensions in Semiconductor Structure (With 26 Figures).- Strong Localisation.- Weak Localisation.- Dimensionality Transitions in the Conductivity.- (a) 3D to 2D.- (b) 2D to 1D.- The Quantum Hall Effect.- References.- 14. RHEED and Photoemission Studies of Semiconductors Grown in-situ by MBE (With 20 Figures).- 14.1 Overview.- 14.2 Basis of Experimental Approach.- 14.2.1 Molecular Beam Epitaxy.- 14.2.2 Surface Reconstruction and RHEED.- 14.2.3 Angular Resolved Photoemission.- 14.3 The Growth Process.- 14.3.1 Growth Dynamics.- 14.3.2 Surface Stoichiometry and Reconstruction.- 14.3.3 Surface Morphology Effects.- 14.4 Electronic Surface Structure Determination.- 14.4.1 Identification of Surface and Bulk States.- 14.4.2 Bulk Valence Bands.- 14.4.3 Surface States: Energy Bands and Symmetries.- 14.4.4 Semiconductor Heterojunctions.- 14.5 Core Level Photoemission.- 14.5.1 Surface Chemistry.- 14.5.2 Heterojunctions.- References.- 15. Metal-Semiconductor Interfaces and Schottky Barriers (With 11 Figures).- 15.I Introduction.- 15.II Metal/Semiconductor Interface Reactions.- 15.III Metal/Si Interface Chemistry.- 15.III.A. Simple-Metal/Si and Noble-Metal/Si Interfaces.- 15.III.B. Transition-Metal/Si and Rare-Earth/Si Interfaces.- 15.III.C. Interfacial Silicide Formation.- 15.III.D. The Silicide/Si Interface.- 15.III.E. Low Temperature Interdiffusion.- 15.III.F. Influence of Interface Contamination.- 15.IV Metal/III–V Interface Chemistry.- 15.V The Schottky Barrier Problem.- 15.V.A. Defect Model.- 15.V.B. Chemical Bonding and Reaction.- 15.V.C. Inhomogeneity of Reaction Products.- 15.VI Microscopic Aspects of the Schottky Barrier.- References.- Contribution.- Catalytic Effect of Near-Noble Metals on Si Oxidation (With 2 Figures).- V Optical Properties.- 16. Raman and Infrared Spectroscopy of Layered Structures (With 1 Figure).- 16.1 Introduction.- 16.2 Mathematical Considerations.- 16.3 Organic Thin Film Preparation.- 16.4 Infrared Spectroscopy of Thin Films.- 16.5 Raman Spectroscopy with Optical Guided Waves.- 16.6 Raman Scattering at an Surface by Surface Plasmons.- 16.7 Conclusion.- References.- 17. Brillouin Scattering in CaAs-Ga1 ?Alx As Superlattices (With 4 Figures).- 17.I Introduction.- 17.II Bulk Vibrations in GaAs-Ga1?xAlxAs Superlattices.- 17.II.A. General Features of the Phonon Dispersion Curves.- 17.II.B. The Theory of Elasticity and the Folding of the Longitudinal Branch.- 17.II.C. Light Scattering by the Modes of the Folded Acoustic Branch.- 17.III Brillouin Scattering by Rayleigh Surface Waves.- 17.III.A. Rayleigh Surface Wave Propagation.- 17.III.B. Experimental Results.- 17.IV. Conclusion.- References.- 18. Nonlinear Surface Polaritons (With 8 Figures).- 18.1 Introduction.- 18.2 Nonlinear Single Interface Waves.- 18.3 A Film Bounded by Nonlinear Media.- 18.3.a. Bounding Media with Positive Nonlinearities.- 18.3.b. Bounding Media with Negative Nonlinearities.- 18.3.c. Bounding Media with Positive and Negative Nonlinearities.- 18.4 Experimental Verification.- 18.5 Discussion.- References.- 19. Surface Plasmon Emission as a Probe of Hot-Electron Dynamics (With 12 Figures).- 19.1 Introduction.- 19.II Light Emission from Tunnel Junctions.- 19.III Electron Injector Structures.- References.- 20. Spectroscopy of Two Dimensional Plasmas in Semiconductor Heterostructures (With 7 Figures).- 20.1 Introduction.- 20.2 Light Scattering Spectroscopy.- 20.3 Optical Processes of 2D Plasma.- 20.4 Concluding Remarks.- References.- Contribution.- Surface Coherent Anti-Stokes Raman Spectroscopy.- VI Magnetic Properties.- 21. Surface Magnetism by Spin Polarized Electrons (With 1 Figure).- 21.1 Introduction.- 21.2 Elastic Exchange Scattering of Electrons.- 21.3 Inelastic Exchange Scattering of Electrons.- 21.4 Spin Polarization of Auger-Electrons.- 21.5 Low-Energy Cascade and Threshold Photoelectrons.- 21.6 Conclusion.- References.- 22. Magnetism at Interfaces and Surfaces, as Probed by Neutron Scattering (With 7 Figures).- 22.1 Introduction. Why Neutrons?.- 22.2 Magnetic Superlattices.- 22.3 Magnetism at the Surface.- 22.4 Conclusions.- References.- Contribution.- Long Wavelength Bulk and Surface Spin Waves in Metallic Superlattices (With 1 Figure).- Index of Contributors.