Hard Copper Boride with Exceptional Conductivity
Copper and boron seldom engage in reaction at ambient pressure. The few reports on copper-doped boron compounds that exist in the literature often lack definitive stoichiometry. Here, we report successful synthesis of Cu_{2-δ}B_{25} single crystals (δ∼0.03, indicating Cu understoichiometry) via a high-pressure melting method using copper and β-rhombohedral boron as precursors. Crystals thus synthesized are characterized by a tetragonal boron sublattice, within which Cu atoms are either partially or fully situated at different interstices between B_{12} icosahedra. The crystals possess a high Vickers hardness of 26.5 GPa and an unusually high electrical conductivity of 1.19×10^{5} S/m-the highest conductivity among the icosahedron-based borides. Hall measurements reveal a notable p-n conduction type transition around 30 GPa. This transition, alongside the remarkable conductivity, is potentially modulated by the copper content and its valence states within the structure. The synthesis of Cu_{2-δ}B_{25} not only broadens the spectrum of hard materials but also opens new avenues for innovative modulation of electronic properties in boron-rich compounds, with promising technological implications.
Authors
- Xiang‐Feng Zhou (ORCID: https://orcid.org/0000-0001-8651-9273)
- Yongjun Tian (ORCID: https://orcid.org/0000-0003-2798-0638)
- Wentao Hu
- Zhisheng Zhao (ORCID: https://orcid.org/0000-0001-8492-0151)
- Yufei Gao (ORCID: https://orcid.org/0000-0002-8500-3870)
- Changzeng Fan (ORCID: https://orcid.org/0000-0001-6727-5912)
- Xiao‐Ji Weng (ORCID: https://orcid.org/0000-0003-2486-3129)
- Zhongyuan Liu (ORCID: https://orcid.org/0000-0002-5600-8998)
- Dongzhou Zhang (ORCID: https://orcid.org/0000-0002-6679-892X)
- Jingyu Hou (ORCID: https://orcid.org/0000-0002-6403-9786)
- Xiang Zhang (ORCID: https://orcid.org/0000-0001-6258-8709)
- Bo Xu (ORCID: https://orcid.org/0000-0002-9804-1614)
- Yanbin Wang (ORCID: https://orcid.org/0000-0001-5716-3183)
- Xi Shao
- Guochun Yang (ORCID: https://orcid.org/0000-0002-2265-1600)
- Ming-Xing Huang
- Lin Wang (ORCID: https://orcid.org/0000-0002-1588-588X)
Institutions
- Nankai University (CN)
- Yanshan University (CN)
- University of Chicago (US)
Publication Details
- Journal
- Physical Review Letters
- Published
- 2024-09-23
- DOI
- https://doi.org/10.1103/physrevlett.133.136301
- Citations
- 11
- Primary Topic
- Boron and Carbon Nanomaterials Research
- Type
- article
- Field-Weighted Citation Impact
- 1.29
Funders
- National Science Foundation
- U.S. Department of Energy
- University of Chicago
- National Natural Science Foundation of China
- Natural Science Foundation of Hebei Province
- National Key Research and Development Program of China
- Argonne National Laboratory