EVIDENCE OF A LOW COMPRESSIBILITY CARBON NITRIDE WITH DEFECT-ZINCBLENDE STRUCTURE

A carbon-nitride compound with defect zincbiende structure (P<(31)over bar>m) has been discovered in samples prepared by a chemical precurso r route. Crystallographical (high-resolution electron microscopy and e lectron nanodiffraction) and electron energy loss measurements has bee n performed to identify the material as cubic zincblende with C3N4 com position. Nanoindentation indicates a high elastic recovery and hardne ss. The results agree with detailed ab initio calculations on metastab le structures and compressibility. Our synthesis method is projected t o be a process that could produce large quantities of material by cont rolling the chemical strategy. The new compound has potential applicat ions for high hardness, elasticity and thermal conductivity, materials and thin films. (C) 1997 American Institute of Physics.