Convergence properties of the Brillouin-Wigner type of perturbation expansion: Jon Magne Leinaas, Institute of Physics, University of Oslo, Oslo, Norway; and T. T. S. Kuo, Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 93 KB
• Volume: 110
• Category: Article
• ISSN: 0003-4916
• DOI: 10.1016/0003-4916(78)90044-1

✦ Synopsis

Experiments on plasmon excitation by electrons which scatter at large angles constitute one of the basic sources of information on plasmon in solids. These experiments provide spectra especially rich in detail, of electrons backscattered from targets having a comparatively perfect structure. Besides, these are the only experiments that are possible at low energies of incident electrons when no shooting of thin films can take place. In such experiments the lattice must absolutely be involved in the process of electron backscattering, since the plasmon cannot appreciably affect the direction of motion of electrons. However, the lattice not only causes the appearance of backscattered electrons, but can also affect the very process of plasmon excitation.

In the present paper a theoretical treatment is given of the influence which the lattice exerts on the process of plasmon generation. This influence is displayed through two effects: the bremsstrahlung of plasmons and the density effect. These effects are due to the processes of either the plasmon emission beginning before the termination of the electron-lattice collision or the electron-lattice collision beginning before the termination of electron-plasmon collision event and to the interference of these processes.

The most important result of the theory developed in the paper is that these effects lead to the broadening of the plasmon resonance line, which is of the same, or even greater, order of magnitude than that due to the traditional mechanisms.