The origin of the boson peak and thermal conductivity plateau in low-temperature glasses
Year: 2003
Type: article
Abstract: We argue that the intrinsic glassy degrees of freedom in amorphous solids giving rise to the thermal conductivity plateau and the "boson peak" in the heat capacity at moderately low temperatures are directly connected to those motions giving rise to the two-level-like excitations seen at still lower temperatures. These degrees of freedom can be thought of as strongly anharmonic transitions between the local minima of the glassy energy landscape that are accompanied by ripplon-like domain wall motions of the glassy mosaic structure predicted to occur at T(g) by the random first-order transition theory. The energy spectrum of the vibrations of the mosaic depends on the glass transition temperature, the Debye frequency, and the molecular length scale. The resulting spectrum reproduces the experimental low-temperature boson peak. The "nonuniversality" of the thermal conductivity plateau depends on k(B)T(g)omega(D) and arises from calculable interactions with the phonons.
Authors: Vassiliy Lubchenko, Peter G. Wolynes
Institution: University of California San Diego
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2143128989