Abstract
Recently, the domains of low-dimensional (low-D) materials and disordered materials have been brought together by the demonstration of several new low-D, disordered systems. The thermal transport properties of these systems are not well-understood. Using amorphous graphene and glassy diamond nanothreads as prototype systems, we establish how structural disorder affects vibrational energy transport in low-dimensional, but disordered, materials. Modal localization analysis, molecular dynamics simulations, and a generalized model together demonstrate that the thermal transport properties of these materials exhibit both similarities and differences from disordered 3D materials. In analogy with 3D, the low-D disordered systems exhibit both propagating and diffusive vibrational modes. In contrast to 3D, however, the diffuson contribution to thermal transport in these low-D systems is shown to be negligible, which may be a result of inherent differences in the nature of random walks in lower dimensions. Despite the lack of diffusons, the suppression of thermal conductivity due to disorder in low-D systems is shown to be mild or comparable to 3D. The mild suppression originates from the presence of low-frequency vibrational modes that maintain a well-defined polarization and help preserve the thermal conductivity in the presence of disorder.
Original language | English (US) |
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Pages (from-to) | 4763-4772 |
Number of pages | 10 |
Journal | Nano letters |
Volume | 16 |
Issue number | 8 |
DOIs | |
State | Published - Aug 10 2016 |
Keywords
- Phonons
- diamond nanothreads
- disorder
- graphene
- vibrational energy transport
ASJC Scopus subject areas
- Bioengineering
- General Chemistry
- General Materials Science
- Condensed Matter Physics
- Mechanical Engineering