Decoupling between propagating acoustic waves and two-level systems in hydrogenated amorphous silicon
| Autor: | Xiao Liu, Thomas Metcalf, Daniel Queen, H. C. Jacks, Frances Hellman, Manel Molina-Ruiz |
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| Rok vydání: | 2021 |
| Předmět: |
Amorphous silicon
Coupling constant Condensed Matter - Materials Science Materials science Hydrogen Condensed matter physics chemistry.chemical_element Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Physics - Applied Physics 02 engineering and technology Decoupling (cosmology) Acoustic wave Chemical vapor deposition Applied Physics (physics.app-ph) 021001 nanoscience & nanotechnology 01 natural sciences Annealing (glass) chemistry.chemical_compound chemistry 0103 physical sciences 010306 general physics 0210 nano-technology Order of magnitude |
| DOI: | 10.48550/arxiv.2105.02513 |
| Popis: | Specific heat measurements of hydrogenated amorphous silicon prepared by hot-wire chemical vapor deposition show a large density of two-level systems at low temperature. Annealing at 200 {\deg}C, well below the growth temperature, does not significantly affect the already-low internal friction or the sound velocity, but irreversibly reduces the non-Debye specific heat by an order of magnitude at 2 K, indicating a large reduction of the density of two-level systems. Comparison of the specific heat to the internal friction suggests that the two-level systems are uncharacteristically decoupled from acoustic waves, both before and after annealing. Analysis yields an anomalously low value of the coupling constant, which increases upon annealing but still remains anomalously low. The results suggest that the coupling constant value is lowered by the presence of hydrogen. Comment: 14 pages, 3 figures, 1 table |
| Databáze: | OpenAIRE |
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