Native surface oxide turns alloyed silicon membranes into nanophononic metamaterials with ultralow thermal conductivity
| Autor: | Daniele Selli, Shiyun Xiong, Sanghamitra Neogi, Davide Donadio |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Silicon
Phonon Mean free path Fluids & Plasmas Oxide chemistry.chemical_element FOS: Physical sciences Germanium 02 engineering and technology 01 natural sciences chemistry.chemical_compound Condensed Matter::Materials Science Thermal conductivity Engineering 0103 physical sciences 010306 general physics Physics Condensed Matter - Materials Science Condensed matter physics Resonance Materials Science (cond-mat.mtrl-sci) 021001 nanoscience & nanotechnology cond-mat.mtrl-sci Membrane chemistry Chemical physics Physical Sciences Chemical Sciences 0210 nano-technology |
| Zdroj: | Xiong, S; Selli, D; Neogi, S; & Donadio, D. (2017). Native surface oxide turns alloyed silicon membranes into nanophononic metamaterials with ultralow thermal conductivity. Physical Review B, 95(18). doi: 10.1103/PhysRevB.95.180301. UC Davis: Retrieved from: http://www.escholarship.org/uc/item/59j0p365 Physical Review B, vol 95, iss 18 |
| Popis: | A detailed understanding of the relation between microscopic structure and phonon propagation at the nan oscale is essential to design materials with desired phononic and thermal properties.Here we uncover a new mechanism of phonon interaction in surface oxidized membranes, i.e., native oxide layers interact with phonons in ultra-thin silicon membranes through local resonances. The local resonances reduce the low frequency phonon group velocities and shorten their mean free path. This effect opens up a new strategy for ultralow thermal conductivity design as it complements the scattering mechanism which scatters higher frequency modes effectively. The combination of native oxide layer and alloying with germanium in concentration as small as 5% reduces the thermal conductivity of silicon membranes to 100 time lower than the bulk. In addition, the resonance mechanism produced by native oxide surface layers is particularly effective for thermal condutivity reduction even at very low temperatures, at which only low frequency modes are populated. Comment: 6 pages, 5 figures, Accepted for publication in Physical Review B |
| Databáze: | OpenAIRE |
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