A DFT study on the transition mechanism of cBN single crystal

作者：Xu, Bin^*; Shi, Yongpeng; Lv, Meizhe; Guo, Quanhai; Wang, Gongzhen

来源：Integrated Ferroelectrics, 2017, 182(1): 161-169.

DOI：10.1080/10584587.2017.1352412

• DFT theory
• surface energy
• cubic boron nitride
• transition mechanism
• high temperature and high pressure

Using first-principle method based on density functional theory, the surface energy of the low-index surfaces of hexagonal boron nitride (hBN) and cubic boron nitride (cBN) has been studied to reveal the transition mechanism of cBN single crystal under high temperature and high pressure (HTHP). The surface energy of hBN (110) , (100) , (0001) facets and cBN (110), (100) , (111) facets using the GGA is 0.200eV, 0.427eV, 0.336eV and 0.220eV, 0.430eV, 0.410eV under 1800K and 5.5GPa, respectively. And the surface energy values of the hBN and cBN facets are 0.221eV, 0.444eV, 0.354eV and 0.250eV, 0.436eV, 0.475eV under 2000K and 6.0GPa, respectively. It is found that the lattice plane of (100) in hBN is consecutive with plane (100) of cBN, and relative difference of the two facets in surface energy is only 0.7% and 1.2% under 1800K, 5.5GPa and 2000K, 6.0GPa, respectively. According to the Modified Thomas-Fermi-Dirac electron theory (TFDC), the direct transition of hBN into cBN can be induced. This indicates that cBN is most likely to be transformed by the hBN under HTHP from the perspective of surface energy of hBN and cBN.

• 出版日期2017
• 单位山东大学; 山东建筑大学