Physics – Condensed Matter – Soft Condensed Matter
Scientific paper
2002-10-02
Physics
Condensed Matter
Soft Condensed Matter
4 pages, 4 figures; completely revised version with new results
Scientific paper
The high-frequency excitations in glasses and supercooled liquids belong to the great mysteries of the physics of condensed matter. While the fast process, located at GHz-THz, can be interpreted as encaged molecular motion, the occurrence of the boson peak (BP), dominating at THz frequencies, still is controversially debated. Two scenarios have evolved during recent years: the BP is truly collective in nature or, alternatively, it results from localized modes. To help solving this controversy, we have investigated the high-frequency dielectric loss of plastic crystals (PCs), having long-range translational but no orientational order. Having in mind the well-defined phonon modes in PCs compared to canonical glasses, and the infrared silence of acoustic phonon modes, millimeter-wave and far-infrared spectroscopy should provide valuable hints on the true origin of the BP. Here we show that PCs exhibit a BP-like feature with markedly different spectral shape compared to canonical glasses, evidencing that mixing of collective phonon with local relaxational modes causes the BP. In addition, we find clear evidence for a fast process also in PCs.
Loidl Alois
Lunkenheimer P.
No associations
LandOfFree
'Boson peak' and high-frequency excitations in glassy crystals does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with 'Boson peak' and high-frequency excitations in glassy crystals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 'Boson peak' and high-frequency excitations in glassy crystals will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-24545