In search of new candidates for ultra-hard materials: the ternary BC3N3 stoichiometry Original Research Article

Starting from formerly investigated graphitic like C3N4, selective substitution of nitrogen with boron led to model structures for the experimentally observed BC3N3 stoichiometry. Investigations of the geometry optimisation and of the electronic properties were carried out using pseudo potential and full potential computations in the framework of the local density functional theory for the two and three dimensional structures (2D and 3D). They lead to propose a precursor (2D), a β-structure and a new ultra hard rhombohedral compound with a hardness (B0∼358 GPa) that reaches the range of formerly studied BC2N structures built from hexagonal and cubic diamond.