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Main Authors: Yan, Yuchao, Liu, Yingying, Wang, Ziyi, Liu, Da, Gao, Xu, Wang, Yan, Li, Cheng, Ma, KeKe, Xia, Ning, Jin, Zhu, Deng, Tianqi, Zhang, Hui, Yang, Deren
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2409.14681
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author Yan, Yuchao
Liu, Yingying
Wang, Ziyi
Liu, Da
Gao, Xu
Wang, Yan
Li, Cheng
Ma, KeKe
Xia, Ning
Jin, Zhu
Deng, Tianqi
Zhang, Hui
Yang, Deren
author_facet Yan, Yuchao
Liu, Yingying
Wang, Ziyi
Liu, Da
Gao, Xu
Wang, Yan
Li, Cheng
Ma, KeKe
Xia, Ning
Jin, Zhu
Deng, Tianqi
Zhang, Hui
Yang, Deren
contents Grain boundaries have extensive influence on the performance of crystal materials. However, the atomic-scale structure and its relation with local and crystallographic symmetries remain elusive in low-symmetry crystals. Herein, we find that the local pseudo-mirror-symmetric atomic layer is the common physical origin of a series of highly coherent grain boundaries in the low-symmetry $β$-Ga2O3 crystal. These include the (100) twin boundary and an emerging series of $(h-1'0'2)/(h+1'0'\bar{2})$ coherent asymmetric grain boundaries (CAGBs). Owing to the local pseudo-mirror symmetry and the special geometric relation of the $β$-Ga2O3 conventional cell, these CAGBs place 80% of the boundary atoms in pseudo-coincident sites, exhibiting high coherence under the coincident-site lattice model. With a combination of density functional theory calculations, Czochralski growth experiment, and atomic-scale characterizations, the structure and stability of the $(002)/(20\bar{2})$-A CAGB are confirmed, with a boundary energy density as low as 0.36 J/m2. This CAGB is responsible for the spontaneous formation of a twinned defect facet at the surface steps during the epitaxy growth of $β$-Ga2O3, warranting a substrate orientation selection rule for $β$-Ga2O3. Through this study, we provide insights into the grain boundary physics in the low-symmetry $β$-Ga2O3 crystal while emphasizing the importance of the local pseudo-symmetries in the low-symmetry crystals.
format Preprint
id arxiv_https___arxiv_org_abs_2409_14681
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Highly coherent grain boundaries induced by local pseudo-mirror symmetry in $β$-Ga2O3
Yan, Yuchao
Liu, Yingying
Wang, Ziyi
Liu, Da
Gao, Xu
Wang, Yan
Li, Cheng
Ma, KeKe
Xia, Ning
Jin, Zhu
Deng, Tianqi
Zhang, Hui
Yang, Deren
Materials Science
Grain boundaries have extensive influence on the performance of crystal materials. However, the atomic-scale structure and its relation with local and crystallographic symmetries remain elusive in low-symmetry crystals. Herein, we find that the local pseudo-mirror-symmetric atomic layer is the common physical origin of a series of highly coherent grain boundaries in the low-symmetry $β$-Ga2O3 crystal. These include the (100) twin boundary and an emerging series of $(h-1'0'2)/(h+1'0'\bar{2})$ coherent asymmetric grain boundaries (CAGBs). Owing to the local pseudo-mirror symmetry and the special geometric relation of the $β$-Ga2O3 conventional cell, these CAGBs place 80% of the boundary atoms in pseudo-coincident sites, exhibiting high coherence under the coincident-site lattice model. With a combination of density functional theory calculations, Czochralski growth experiment, and atomic-scale characterizations, the structure and stability of the $(002)/(20\bar{2})$-A CAGB are confirmed, with a boundary energy density as low as 0.36 J/m2. This CAGB is responsible for the spontaneous formation of a twinned defect facet at the surface steps during the epitaxy growth of $β$-Ga2O3, warranting a substrate orientation selection rule for $β$-Ga2O3. Through this study, we provide insights into the grain boundary physics in the low-symmetry $β$-Ga2O3 crystal while emphasizing the importance of the local pseudo-symmetries in the low-symmetry crystals.
title Highly coherent grain boundaries induced by local pseudo-mirror symmetry in $β$-Ga2O3
topic Materials Science
url https://arxiv.org/abs/2409.14681