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This content will become publicly available on January 11, 2017

Title: Tensile strains give rise to strong size effects for thermal conductivities of silicene, germanene and stanene

Based on first principles calculations and self-consistent solution of linearized Boltzmann-Peierls equation for phonon transport approach within a three-phonon scattering framework, we characterize lattice thermal conductivities k of freestanding silicene, germanene and stanene under different isotropic tensile strains and temperatures. We find a strong size dependence of k for silicene with tensile strain, i.e., divergent k with increasing system size, in contrast, the intrinsic room temperature k for unstrained silicene converges with system size to 19.34 W/m–1 K–1 by 178 nm. The room temperature k of strained silicene becomes as large as that of bulk silicon by 84 m, indicating the possibility of using strain in silicene to manipulate k for thermal management. The relative contribution to the intrinsic k from out-of-plane acoustic modes is largest for unstrained silicene, –39% at room temperature. The single mode relaxation time approximation, which works reasonably well for bulk silicon, fails to appropriately describe phonon thermal transport in silicene, germanene and stanene within the temperature range considered. For large samples of silicene, k increases with tensile strain, peaks at –7% strain and then decreases with further strain. In germanene and stanene increasing strain hardens and stabilizes long wavelength out-of-plane acoustic phonons, and leads tomore » similar k behaviors to those of silicene. As a result, these findings further our understanding of phonon dynamics in group-IV buckled monolayers and may guide transfer and fabrication techniques of these freestanding samples and engineering k by size and strain for applications of thermal management and thermoelectricity.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Jinan Univ., Guangzhou (China)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Hong Kong Polytechnic Univ., Kowloon (China); Hong Kong Polytechnic Univ. Shenzhen Research Institute, Shenzhen (China)
  4. Hong Kong Polytechnic Univ., Kowloon (China)
Publication Date:
OSTI Identifier:
1238749
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Nanoscale
Additional Journal Information:
Journal Volume: 8; Journal Issue: 6; Journal ID: ISSN 2040-3364
Publisher:
Royal Society of Chemistry
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English