Glass-Like Thermal Conductivity in Nanostructures of a Complex Anisotropic Crystal
| Autor: | Song Jin, Li Shi, Jeremy M. Higgins, Jaehyun Kim, Jesús Carrete, John P. DeGrave, N. Mingo, Annie Weathers, Arden L. Moore |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Condensed Matter - Materials Science Materials science Nanostructure Condensed matter physics Anisotropic crystal Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences 7. Clean energy Wavelength Thermal conductivity Lattice constant Molecular vibration 0103 physical sciences Energy transformation 0210 nano-technology Anisotropy |
| Popis: | Size effects on vibrational modes in complex crystals remain largely unexplored, despite their importance in a variety of electronic and energy conversion technologies. Enabled by advances in a four-probe thermal transport measurement method, we report the observation of glass-like thermal conductivity in $\ensuremath{\sim}20$-nm-thick single crystalline ribbons of higher manganese silicide, a complex, anisotropic crystal with a $\ensuremath{\sim}10$-nm-scale lattice constant along the incommensurate $c$ axis. The boundary-scattering effect is strong for many vibrational modes because of a strong anisotropy in their group velocities or diffusive nature, while confinement effects are pronounced for acoustic modes with long wavelengths along the $c$ axis. Furthermore, the transport of the nonpropagating, diffusive modes is suppressed in the nanostructures by the increased incommensurability between the two substructures as a result of the unusual composition of the nanostructure samples. These unique effects point to diverse approaches to suppressing the lattice thermal conductivity in complex materials. |
| Databáze: | OpenAIRE |
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