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Enhancing anisotropy of thermal conductivity based on tandem acoustic Bragg reflectors

Lee, Hun and Lee, Sehyuk and So, Soonsung and Park, Sang-Hyuk and Minnich, Austin J. and Lee, Joo-Hyoung and Jho, Young-Dahl (2022) Enhancing anisotropy of thermal conductivity based on tandem acoustic Bragg reflectors. Journal of Applied Physics, 131 (7). Art. No. 075110. ISSN 0021-8979. doi:10.1063/5.0069575.

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Thermal metamaterials have emerged as one of the latest research topics in applied science due to breakthrough advantages in modifying conductive heat flux. An acoustic Bragg reflector (ABR), composed of alternating arrays of two materials with contrasting acoustic impedances, is anticipated to coherently manipulate the transport properties of thermally important phonon branches by attaining interface roughness close to the monoatomic scale. However, there is a lack of research on how a narrow portion of the phononic band of a particular ABR can be extended to cover the entire thermal spectrum. Here, we report a modeling study of thermal transport using ABR, representatively based on GaAs/AlAs, GaN/AlN, or HfO₂/SiO₂ superlattices. Our calculations show that the anisotropy of thermal conductivity in HfO₂/SiO₂ can be significantly improved by tandemizing four different ABR layers, thus approaching the theoretically anticipated values based on monolayered materials. This work demonstrates how the tandem ABR can expand forbidden phononic bands beyond that occupied by a single ABR and proposes a practical strategy for realizing spectrally functionalized thermal properties from compound semiconductor materials that can be directly integrated into the existing device fabrication processes.

Item Type:Article
Related URLs:
URLURL TypeDescription
Lee, Hun0000-0003-3304-3712
So, Soonsung0000-0002-4732-3515
Park, Sang-Hyuk0000-0001-5166-2352
Minnich, Austin J.0000-0002-9671-9540
Lee, Joo-Hyoung0000-0002-7637-9825
Jho, Young-Dahl0000-0002-5898-0406
Additional Information:© 2022 Author(s). Published under an exclusive license by AIP Publishing. Submitted: 01 September 2021 • Accepted: 01 February 2022 • Published Online: 18 February 2022. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (No. 2018R1A2B6008101) and the Ministry of Education (No. 2021R1I1A2059710). DATA AVAILABILITY. The data that support the findings of this study are available from the corresponding author upon reasonable request. The authors have no conflicts to disclose.
Funding AgencyGrant Number
National Research Foundation of Korea2018R1A2B6008101
National Research Foundation of Korea2021R1I1A2059710
Issue or Number:7
Record Number:CaltechAUTHORS:20220222-706499000
Persistent URL:
Official Citation:Hun Lee, Sehyuk Lee, Soonsung So, Sang-Hyuk Park, Austin J. Minnich, Joo-Hyoung Lee, and Young-Dahl Jho, "Enhancing anisotropy of thermal conductivity based on tandem acoustic Bragg reflectors", Journal of Applied Physics 131, 075110 (2022)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113522
Deposited By: George Porter
Deposited On:24 Feb 2022 20:57
Last Modified:24 Feb 2022 20:57

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