Ulteriori informazioni
In recent years substantial progress has been made in the detection of surface phonons owing to considerable improvements in inelastic rare gas scattering tech niques and electron energy loss spectroscopy. With these methods it has become possible to measure surface vibrations in a wide energy range for all wave vectors in the two-dimensional Brillouin zone and thus to deduce the complete surface phonon dispersion curves. Inelastic atomic beam scattering and electron energy loss spectroscopy have started to play a role in the study of surface phonons similar to the one played by inelastic neutron scattering in the investigation of bulk phonons in the last thirty years. Detailed comparison between experimen tal results and theoretical studies of inelastic surface scattering and of surface phonons has now become feasible. It is therefore possible to test and to improve the details of interaction models which have been worked out theoretically in the last few decades. At this point we felt that a concise, coherent and self-contained guide to the rapidly growing field of surface phonons was needed.
Sommario
1. Introduction.- 2. Surface Acoustic Waves.- 2.1 Surface Acoustic Waves on Various Media.- 2.2 Generation and Detection of Surface Acoustic Waves.- 2.3 Some Applications of Surface Acoustic Waves.- References.- 3. The Green's Function Method in the Surface Lattice Dynamics of Ionic Crystals.- 3.1 Outline of the Time-Independent Green's Function Method.- 3.2 The Green's Function Method in Surface Dynamics.- 3.3 The Intrinsic Perturbation for a Semi-Infinite Lattice.- 3.4 The Electronic Contribution to Surface Dynamics in the Framework of Shell Models.- 3.5 Surface Phonon Polaritons.- 3.6 Surface Vibrations in Alkali Halides.- 3.7 Further Developments: The Study of Surface Phonon Anomalies.- References.- 4. Study of Surface Phonons by the Slab Method.- 4.1 Formalism.- 4.2 Computational Considerations.- 4.3 Interaction Models.- 4.4 Results.- 4.5 Derived Physical Quantities.- 4.6 Concluding Remarks.- References.- 5. Experimental Determination of Surface Phonons by Helium Atom and Electron Energy Loss Spectroscopy.- 5.1 Theoretical Background.- 5.2 Kinematics.- 5.3 Helium Scattering.- 5.4 Electron Scattering.- 5.5 Intensities.- 5.6 Discussion of Experimental Results and Summary.- References.- 6. Theory of Helium Scattering from Surface Phonons.- 6.1 Kinematics.- 6.2 Dynamical Theory: General Considerations.- 6.3 One-Phonon Exchange Processes.- 6.4 The Inelastic Atom-Surface Interaction.- References.- 7. The Study of Surface Phonons by Electron Energy Loss Spectroscopy: Theoretical and Experimental Considerations.- 7.1 A Brief Review.- 7.2 The Surface Phonon Excitation Mechanism in the Impact Regime.- 7.3 The Green's Function Approach to Spectral Density Calculations.- 7.4 Calculations of the Cross Section for Surface Phonon Excitation.- 7.5 Concluding Remarks.-References.- 8. Vibrational Properties of Clean Surfaces: Survey of Recent Theoretical and Experimental Results.- 8.1 Ionic Crystals.- 8.2 Metals.- 8.3 Miscellaneous.- References.
