Elastic constants and anisotropy of β-BC2N under pressure

Structural, elastic constants and anisotropy of the potential superhard orthorhombic structure boron carbonitride beta-BC2N under hydrostatic pressure up to 100 GPa have been studied using density functional theory within the local density approximation (LDA) as well as the generalized gradient approximation (GGA) for exchange and correlation. The results are in excellent agreement with available experimental data and other theoretical results. Changes of lattice constants, the cell volume, elastic constants, and elastic anisotropy of beta-BC2N under hydrostatic loading are examined, and the bulk modulus B-0 and its pressure derivative B'(0) are fitted from the volume-pressure relation. It is concluded that beta-BC2N is a brittle and hard material in nature up to 100 GPa and is next to diamond in hardness. An analysis for the calculated elastic constant has been made to reveal the mechanical stability of beta-BC2N up to 100 GPa. (C) 2010 Elsevier B.V. All rights reserved.