Suppression of tunneling two-level systems in ultrastable glasses of indomethacin

• DOI: 10.1073/pnas.1405545111
• Publication Date: 2014-07-08T03:01:33Z
• Authors: Tomás Pérez-Casta...; Cristian Rodrígue...; Javier Rodríguez-...; Miguel A. Ramos
• Keywords: Condensed Matter - Materials Science; Materials Science (cond-mat.mtrl-sci); Soft Condensed Matter (cond-mat.soft); FOS: Physical sciences; Disordered Systems and Neural Networks (cond-mat.dis-nn); Condensed Matter - Disordered Systems and Neural Networks; Condensed Matter - Soft Condensed Matter

Glasses and other non-crystalline solids exhibit thermal acoustic properties at low temperatures anomalously different from those found in crystalline solids, with a remarkable degree of universality. Below few K, these universal have been successfully interpreted using the Tunneling Model, which has enjoyed (almost) unanimous recognition for decades. Here we present low-temperature specific-heat measurements ultrastable glasses indomethacin that clearly show disappearance ubiquitous linear contribution traditionally ascribed to existence tunneling two-level systems (TLS). When thin-film sample is thermally converted into conventional glass, material recovers typical amount TLS. This suppression TLS argued be due their particular anisotropic layered character, strongly influences dynamical network may hinder isotropic interactions among low-energy defects, rather than thermodynamic stabilization itself. explanation lend support criticisms by Leggett others standard although more experiments kinds are needed ascertain this hypothesis.