Abstract
The specific heat and thermal conductivity of neutron-irradiated crystalline quartz have been measured to ≲0.1 K. Four types of low-energy excitations are observed, two of which may be removed selectively by heat treatment. From the and of annealed samples it is shown that the localized excitations found in vitreous silica also occur in neutron-damaged quartz. These excitations cause the unusual low-temperature behavior which is characteristic of amorphous materials. The properties of these excitations appear to remain unchanged as the total density of excitations is reduced by a factor of ≈ 40. At greater dilution, the localized excitations are masked by the effects of other, unidentified excitations.
- Received 11 August 1980
DOI:https://doi.org/10.1103/PhysRevB.23.474
©1981 American Physical Society