The low-temperature universal properties in disordered and amorphous solids are considered. We introduce a model that includes two types of two-level systems (TLSs), which, based on their local symmetry, interact weakly or strongly with the phonon field. This accounts well for the experimental results and addresses some long-standing questions: the nature of the TLSs, the smallness and universality of the phonon attenuation, and the energy scale of 3 K below which universality is observed. Our model describes disordered lattices; we also discuss its application to amorphous solids.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 5 Nov 2013|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics