Relaxation due to Incoherent Tunnelling in Dielectric Glasses
arXiv:cond-mat/9410062 · doi:10.1209/0295-5075/27/6/008
Abstract
A new relaxation mechanism is shown to arise from overdamped two-level systems above a critical temperature $T^*\approx 5$ K, thus yielding an explanation for experimental observations in dielectric glasses in the temperature range between $T^*$ and the relaxation peak at 50 K. Using the distribution function of the tunnelling model for the parameters of the two-level systems, both the linear decrease of the sound velocity and the linear increase of the absorptionup to the relaxation maximum, are quantitatively accounted for by our theory.
9 pages, Rev-Tex, Europhys.Lett, 27, 457 (1994)