Synthesis of Semimetallic BC_3.3N with Orthorhombic Structure at High Pressure and Temperature

Abstract

A new BC3.3N crystalline compound with orthorhombic structure has been synthesized using an amorphous B−C−N precursor at 6 GPa and 1773 K. Results of energy-dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS) experiments show that the compound has a 1.04:3.27:1 B:C:N chemical stoichiometry. The lattice parameters of BC3.3N crystal were obtained to be a = 6.610 (± 0.004) Å, b = 4.977 (± 0.006) Å, and c = 8.509 (± 0.008) Å by X-ray diffraction (XRD) and select area electron diffraction (SAED). The measurement of resistivity shows that this BC3.3N compound is semimetallic conductor with resistivity about 2.99 × 10−3 Ω cm at 300 K. On the basis of the analyses of XRD refinement and EELS results about the bonding situation, one possible conducting BC3.3N (B3C10N3) model with a space group of Pmma (No. 51) is proposed. The band structure and density of state of this model were calculated by CASTEP. The atomic positions, bond lengths, and bond angles are given.