DIPOLE GAP EFFECTS IN LOW-ENERGY EXCITATION SPECTRUM OF AMORPHOUS SOLIDS - THEORY FOR DIELECTRIC-RELAXATION

The long-range interaction of two-level systems in dielectric glasses influences the density of states and consequently the non-equilibrium dielectric response. The AC dielectric susceptibility is analyzed unde r rapid switching on of the DC electric field. The instantaneous incre ase of the dielectric susceptibility together with its subsequent loga rithmic relaxation, observed experimentally, are explained in the fram ework of a model of weakly interacting two-level systems. The temperat ure and frequency dependences of the relaxation rate are found to be i n a good agreement with the experimental data.