Electron-solid interactions

The crystal surface is imagined to consist of individual atomic layers parallel to the surface. Whenever convenient, the LEED electrons between these layers are represented by a set of plane waves (to each diffracted beam corresponds one plane wave), as the electron-solid interaction potential is assumed to be a constant between the layers. 

There are two major features of the electron-solid interaction evidenced in the 1-V profiles and in other scattering data in LEED electron diffraction that the theory must provide for ... 

Finally, electrons can be emitted from a surface as a result of photon-solid or electron solid interactions. When high energy photons or electrons are incident upon sohd samples, several electronic transitions can lead to the emission of electrons. First, if the energy (hv) of an incident photon exceeds that necessary to ionize an atom of the solid, electrons not suffering inelastic collisions will be emitted from the solid with a kinetic energy (KE) given by... 

FIGURE 8.1 A schematic representation of processes taking place during electron-solid interaction. 

Fledin L and Lundqvist S 1969 Effects of electron-electron and electron-phonon interactions on the one-electron states of solids Solid State Phys. 23 1... 

Additional information concerning the mechanisms of solid—solid interactions has been obtained by many diverse experimental approaches, as the following examples testify adsorptive and catalytic properties of the reactant mixture [1,111], reflectance spectroscopy [420], NMR [421], EPR [347], electromotive force determinations [421], tracer experiments [422], and doping effects [423], This list cannot be comprehensive. Electron probe microanalysis has also been used as an analytical (rather than a kinetic) tool [422,424] for the determination of distributions of elements within the reactant mixture. Infrared analyses have been used [425] for the investigation of the solid state reactions between NH3 and S02 at low temperatures in the presence and in the absence of water. 

Ga( Zn), Sn, Te( I) Mossbauer spectroscopy, no modifications of the local symmetry of lattice sites, electronic structure of atoms and intensity of electron-phonon interaction are revealed for Pbi Sn Te solid solutions in the gapless state at 80 and 295 K... 

Let us first review some experiments in which the laser-driven acceleration of electrons has been obtained in laser-solid interactions. 

Calori, C., Combescot, R., Nozieres, P., and Saint-James, D. (1972). A direct calculation of the tunneling current IV. Electron-phonon interaction effects. Solid State Physics 5, 21—42. 

Shirai, M., Suzuki, N. and Motizuki, K., Microscopic Theory of Electron - Phonon Interaction and Superconductivity of BaPbj.jjB Og. Solid State Comm. 60(6) 489 (1986). 

Besides magnetic perturbations and electron-lattice interactions, there are other instabilities in solids which have to be considered. For example, one-dimensional solids cannot be metallic since a periodic lattice distortion (Peierls distortion) destroys the Fermi surface in such a system. The perturbation of the electron states results in charge-density waves (CDW), involving a periodicity in electron density in phase with the lattice distortion. Blue molybdenum bronzes, K0.3M0O3, show such features (see Section 4.9 for details). In two- or three-dimensional solids, however, one observes Fermi surface nesting due to the presence of parallel Fermi surface planes perturbed by periodic lattice distortions. Certain molybdenum bronzes exhibit this behaviour. 

The electrons in a solid interact both with one another and with the lattice vibrations. A theme of this book is the effect of the interaction between electrons in inducing magnetic moments and metal-insulator transitions. Interaction with phonons also has an important effect, particularly in some transitional-metal oxides. In this chapter both kinds of interaction are introduced. 

---