Phonons, Localization, and Thermal Conductivity of Diamond Nanothreads and Amorphous Graphene

Taishan Zhu, Elif Ertekin

Research output: Contribution to journalArticlepeer-review

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 languageEnglish (US)
Pages (from-to)4763-4772
Number of pages10
JournalNano letters
Volume16
Issue number8
DOIs
StatePublished - 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

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