sp2和sp3杂化的B-C-N的第一性原理研究.docVIP

 n B–C–N compounds with mixed hybridization of sp2-like and sp3-like bonds# Luo Xiaoguang1, He Julong2* 5 10 15 20 (1. College of Information Technical Science, Nankai University, TianJin 300071; 2. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, HeBei QinHuangDao 066004) Abstract: In this letter we perform first-principles calculations of the structural and electronical properties of hypothetical bc6-BC4N and N-substituted bc6-BC4N, which are derived from a body center cubic carbon structure. Our calculations show that the former is a semiconductor with an indirect band gap of 0.91 eV and the latter is metallic. The calculated bond length, bond population, and charge density of N-substituted bc6-BC4N indicate that one C-N bond has been broken after N-substitution, which means that the structure is contained with mixed hybridization of sp2-like and sp3-like bonds. At the pressure above 100 GPa, the structure changed to pure sp3-like hybridization. Keywords: B-C-N; hybridization; first-principles 0 Introduction The structural similarity between the carbon and boron nitride (BN) has stimulated intensive research in recent years on the exploring of ternary B–C–N compounds. The B–C–N compounds are expected to have intermediate or even superior properties than those of carbon or BN. Various experimental methods have been used to the synthesis of B–C–N compounds and the hexagonal[1, 2] and wurtzite[3] structures of B–C–N compounds have been reported. The superhard BC2N and BC4N compounds with pseudo-cubic structures have also been synthesized using laser-heated diamond anvil cell and large press.[4, 5] The bulk and shear moduli,[4, 6, 7] Vickers hardness,[4, 8] and 25 30 35 40 Raman spectrum[9] of BC2N compounds have been examined. So far, the detailed crystal structure of synthesized BCxN compounds is still in progress. Many theoretical works have been done on the structures and properties of BCxN compounds. Because isoe