Small Wave Number Region Research Articles

Theory of Plasmon Damping in Metals. II. Effects of Electron-Ion Interaction

Effects of electron-ion interaction on the plasmon damping in metals are investigated by using a general formulation developed in a previous paper. Damping of a plasmon with small wavenumber q is mainly determined by the processes in which the plasmon dacays into (i) one electron-hole pair by interband transition and (ii) one electron-hole pair with simultaneous absorption or emission of a phonon. These processes give negative q 2 -coefficient of damping in the small wavenumber region. On the other hand, the process in which the plasmon decays into another plasmon with simultaneous absorption or emission of a phonon gives the damping nearly proportional to q . As a whole, with including the contribution of the electron-electron interaction discussed in I, plasmon half-width in Al slightly decreases as q increases in the small q region, while the damping in Na slightly increases with q .