Design of a Series of Metallic BxNx+1 with Tunable Mechanical Properties

Authors：Li, Baozhong; Luo, Kun; Chen, Junyun; Xie, Chenlong; Gao, Yufei; Zhu, Li; Huang, Quan; Ma, Mengdong^*; Zhang, Yang^*; Zhao, Zhisheng; He, Julong^*; Tian, Yongjun

Source：Journal of Physical Chemistry Letters, 2021, 12(7): 1979-1984.

DOI：10.1021/acs.jpclett.1c00040

• HIGH-PRESSURE SYNTHESIS
• CUBIC BORON-NITRIDE
• BN

Here a series of sp(2)-sp(3) BxNx+1 (x = 1, 2, 3, 4, 5, 6) structures was constructed. These structures can be viewed as diamond-like BN blocks connected by single N-N bonds. Elastic constants and phonon dispersion curves confirm that all of the proposed structures are mechanically and dynamically stable. These structures all possess metallicity originating from the conductive channels formed by sp(2)-hybridized N atoms and adjacent sp(3)-hybridized B and N atoms. These structures exhibit tunable mechanical properties with a regular change in the sp(2)/sp(3) ratio. The theoretical Vickers hardness increases and the ductility decreases as the number of diamond-like BN blocks increases, gradually approaching those of c-BN. Moreover, the convex hull at ambient pressure and 50 GPa indicates that high pressure is beneficial in the synthesis of these B-N phases. The simulated X-ray diffraction patterns of these structures were also calculated to provide more information for further experiments.

• Institution
  y; 燕山大学