Title: Antisite Pairs Suppress the Thermal Conductivity of BAs

Abstract

BAs was predicted to have an unusually high thermal conductivity with a room temperature value of 2000 W m^–1 K^–1, comparable to that of diamond. However, the experimentally measured thermal conductivity of BAs single crystals is still lower than this value. To identify the origin of this large inconsistency, we investigate the lattice structure and potential defects in BAs single crystals at the atomic scale using aberration-corrected scanning transmission electron microscopy (STEM). Rather than finding a large concentration of As vacancies (V_As), as widely thought to dominate the thermal resistance in BAs, our STEM results show an enhanced intensity of some B columns and a reduced intensity of some As columns, suggesting the presence of antisite defects with As_B (As atom on a B site) and B_As (B atom on an As site). Additional calculations show that the antisite pair with As_B next to B_As is preferred energetically among the different types of point defects investigated and confirm that such defects lower the thermal conductivity for B_As. Using a concentration of 1.8(8)% (6.6 ± 3.0 × 10²⁰ cm^–3 in density) for the antisite pairs estimated from STEM images, the thermal conductivity is estimated to be 65–100 W m^–1 K^–1, inmore » reasonable agreement with our measured value. Our study suggests that As_B–B_As antisite pairs are the primary lattice defects suppressing thermal conductivity of B_As. Possible approaches are proposed for the growth of high-quality crystals or films with high thermal conductivity. In conclusion by employing a combination of state-of-the-art synthesis, STEM characterization, theory, and physical insight, this work models a path toward identifying and understanding defect-limited material functionality.« less

Authors:

Zheng, Qiang  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-9279-7779"

Polanco, Carlos A.  ^[1];

• Search DOE PAGES for author "Polanco, Carlos A."
• Search DOE PAGES for ORCID "0000-0003-1510-7372"

Du, Mao -Hua  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8796-167X"

Lindsay, Lucas R.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-9645-7993"

Chi, Miaofang  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-0764-1567"

Yan, Jiaqiang  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-6625-4706"

Sales, Brian C.  ^[1]

• Search DOE PAGES for author "Sales, Brian C."
• Search DOE PAGES for ORCID "0000-0002-6335-5912"

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+ Show Author Affiliations

1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

Publication Date:

Thu Sep 06 00:00:00 EDT 2018

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1474871

Alternate Identifier(s):

OSTI ID: 1468867

Grant/Contract Number:  

AC05-00OR22725; AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Letters

Additional Journal Information:

Journal Volume: 121; Journal Issue: 10; Journal ID: ISSN 0031-9007

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE