Single-crystal X-ray diffraction of BC8 carbon near terapascal pressures
Abstract
Whether carbon forms crystalline structures beyond diamond at terapascal pressures remains unresolved. Predicted for nearly four decades, the denser BC8 phase has lacked direct crystallographic evidence. Here we report the first direct crystallographic identification of BC8 carbon, formed as a single crystal from molten carbon during laser-driven decaying-shock compression of [100]-oriented diamond following loading above 1.1 TPa. Using in situ orientation-resolved single-crystal X-ray diffraction, we observe discrete Bragg spots whose spacings and angular relationships are reproduced by a common orientation matrix within each indexed BC8 reflection group, providing constraints beyond powder peak matching. Our single-crystal formation strategy and direct diffraction evidence resolve the decades-long quest for a post-diamond carbon structure, demonstrating how dynamic loading pathways can make predicted high-pressure phases experimentally accessible.
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BibTeX
@misc{sun2026singlecrystal,
title = {{Single-crystal X-ray diffraction of BC8 carbon near terapascal pressures}},
author = {Liang Sun and Bo Chen and Zhiyu He and Pin Yang and Zanyang Guan and Guo Jia and Fan Zhang and Yi Yang and Bo Xu and Pei Guo and Yonggang Liu and Wei Fan and Tao Xi and Yulong Li and Lingbiao Meng and Wei Kang and Zhiyong Xie and Yuqiong Tu and Cheng Ji and Xiuguang Huang and Zhongjing Chen and Ji Yan and Jiamin Yang and Wenge Yang and Toshimori Sekine and Zongqing Zhao and Jiayu Dai and Ho-Kwang Mao},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.06045},
eprint = {2611.06045},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.06045},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Single-crystal X-ray diffraction of BC8 carbon near terapascal pressures
AU - Liang Sun
AU - Bo Chen
AU - Zhiyu He
AU - Pin Yang
AU - Zanyang Guan
AU - Guo Jia
AU - Fan Zhang
AU - Yi Yang
AU - Bo Xu
AU - Pei Guo
AU - Yonggang Liu
AU - Wei Fan
AU - Tao Xi
AU - Yulong Li
AU - Lingbiao Meng
AU - Wei Kang
AU - Zhiyong Xie
AU - Yuqiong Tu
AU - Cheng Ji
AU - Xiuguang Huang
AU - Zhongjing Chen
AU - Ji Yan
AU - Jiamin Yang
AU - Wenge Yang
AU - Toshimori Sekine
AU - Zongqing Zhao
AU - Jiayu Dai
AU - Ho-Kwang Mao
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.06045
UR - https://arxiv.org/abs/2611.06045
AB - Whether carbon forms crystalline structures beyond diamond at terapascal pressures remains unresolved. Predicted for nearly four decades, the denser BC8 phase has lacked direct crystallographic evidence. Here we report the first direct crystallographic identification of BC8 carbon, formed as a single crystal from molten carbon during laser-driven decaying-shock compression of [100]-oriented diamond following loading above 1.1 TPa. Using in situ orientation-resolved single-crystal X-ray diffraction, we observe discrete Bragg spots whose spacings and angular relationships are reproduced by a common orientation matrix within each indexed BC8 reflection group, providing constraints beyond powder peak matching. Our single-crystal formation strategy and direct diffraction evidence resolve the decades-long quest for a post-diamond carbon structure, demonstrating how dynamic loading pathways can make predicted high-pressure phases experimentally accessible.
ER -