Modulation of Thermal Conductivity in Kinked Silicon Nanowires: Phonon Interchanging and Pinching Effects

We perform molecular dynamics simulations to investigate the reduction of the thermal conductivity by kinks in silicon nanowires. The reduction percentage can be as high as 70% at room temperature. The temperature dependence of the reduction is also calculated. By calculating phonon polarization vec...

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Bibliographic Details
Published in:Nano letters 2013-04, Vol.13 (4), p.1670-1674
Main Authors: Jiang, Jin-Wu, Yang, Nuo, Wang, Bing-Shen, Rabczuk, Timon
Format: Article
Language:English
Subjects:
Condensed matter: structure, mechanical and thermal properties
Cross-disciplinary physics: materials science
rheology
Exact sciences and technology
Exchanging
Germanium - chemistry
Heat transfer
Lattice dynamics
Materials science
Mathematical analysis
Molecular Dynamics Simulation
Nanocrystalline materials
Nanoscale materials and structures: fabrication and characterization
Nanostructures - chemistry
Nanowires
Nanowires - chemistry
Phonons
Phonons in low-dimensional structures and small particles
Physics
Quantum wires
Reduction
Silicon
Silicon - chemistry
Surface Properties
Thermal Conductivity
Thermal properties of condensed matter
Thermal properties of small particles, nanocrystals, nanotubes
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Summary:We perform molecular dynamics simulations to investigate the reduction of the thermal conductivity by kinks in silicon nanowires. The reduction percentage can be as high as 70% at room temperature. The temperature dependence of the reduction is also calculated. By calculating phonon polarization vectors, two mechanisms are found to be responsible for the reduced thermal conductivity: (1) the interchanging effect between the longitudinal and transverse phonon modes and (2) the pinching effect, that is, a new type of localization, for the twisting and transverse phonon modes in the kinked silicon nanowires. Our work demonstrates that the phonon interchanging and pinching effects, induced by kinking, are brand-new and effective ways in modulating heat transfer in nanowires, which enables the kinked silicon nanowires to be a promising candidate for thermoelectric materials.
ISSN:1530-6984
1530-6992
DOI:10.1021/nl400127q