Effects of network topology on low-temperature relaxation in Ge-As-Se glasses, as probed by persistent infrared spectral-hole burning

The relaxation of persistent infrared spectral holes burned in the SeH vibrational absorption band at 1.5 K is studied for ten glass compositions in the Ge-As-Se system. It is found that the dominant spectral-hole relaxation rate increases by over 3 orders of magnitude as the average atomic coordination number varies from 2.0 to 2.8. Over the composition range studied, the quantitative form of the nonexponential hole relaxation depends solely on the average coordination number, independent of chemical composition.