Blocking Phonon Transport by Structural Resonances in Alloy-Based Nanophononic Metamaterials Leads to Ultralow Thermal Conductivity

Shiyun Xiong, Kimmo Sääskilahti, Yuriy A. Kosevich, Haoxue Han, Davide Donadio, Sebastian Volz

Research output: Contribution to journalArticleScientificpeer-review

124 Citations (Scopus)

Abstract

Understanding the design rules to obtain materials that enable a tight control of phonon transport over a broad range of frequencies would aid major developments in thermoelectric energy harvesting, heat management in microelectronics, and information and communication technology. Using atomistic simulations we show that the metamaterials approach relying on localized resonances is very promising to engineer heat transport at the nanoscale. Combining designed resonant structures to alloying can lead to extremely low thermal conductivity in silicon nanowires. The hybridization between resonant phonons and propagating modes greatly reduces the group velocities and the phonon mean free paths in the low frequency acoustic range below 4 THz. Concurrently, alloy scattering hinders the propagation of high frequency thermal phonons. Our calculations establish a rationale between the size, shape, and period of the resonant structures, and the thermal conductivity of the nanowire, and demonstrate that this approach is even effective to block phonon transport in wavelengths much longer than the size and period of the surface resonant structures. A further consequence of using resonant structures is that they are not expected to scatter electrons, which is beneficial for thermoelectric applications.

Original languageEnglish
Article number025503
Pages (from-to)1-6
JournalPhysical Review Letters
Volume117
Issue number2
DOIs
Publication statusPublished - 8 Jul 2016
MoE publication typeA1 Journal article-refereed

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