Vapor-deposited glasses provide clearer view of two-level systems

TitleVapor-deposited glasses provide clearer view of two-level systems
Publication TypeJournal Article
Year of Publication2014
AuthorsEdiger, M. D.
JournalPNAS
Volume111
Start Page11232
Issue31
Date Published08/2014
Abstract

Glasses and crystals play different roles in technology. When precise control of local structure is required, as in silicon-based electronics, crystals are used. On the other hand, when macroscopic homogeneity is required, as in optical fibers, glasses are used. The pairing of local disorder and macroscopic homogeneity in glasses is not a coincidence. The range of local packing arrangements present in glassy materials allows “defects,” such as impurities, to be locally accommodated in contrast to crystals for which disruptive grain boundaries are often the consequence. The flexible local packing of glasses also provides an opportunity for materials engineering. Many glasses with different structures and properties can be prepared with exactly the same composition. This last feature is a key element in the experiments of Pérez-Castañeda et al. (1). Pérez-Castañeda et al. report that two different glasses made from the same organic molecule can have dramatically different heat capacities below 1 K.

URLhttp://www.pnas.org/content/111/31/11232.full
DOI10.1073/pnas.1411278111