We study the effect of interactions on the zero-temperature ac conductivity of a two-dimensional Anderson insulator at low frequencies. We show that the enhancement of the real part of conductivity due to the Coulomb correlations in the occupation numbers of localized states results in the change of the sign of the imaginary part within a certain frequency range. As a result, the propagation of a surface plasmon in a localized system becomes possible. We analyze the dispersion law of the plasmon for the two cases: unscreened Coulomb interactions and the interactions screened by a gate electrode spaced by some distance from the electron plane.
Physical Review B
- Pub Date:
- March 1996
- Metal-insulator transitions and other electronic transitions;
- Exchange correlation dielectric and magnetic response functions plasmons;
- Condensed Matter
- latex 22 pages + 2 uuencoded figures