A comparative study of electronic structure and bonding in transition metal monocarbides

The structural, electronic, elastic and bonding properties of four transition metal carbides, ScC, YC (group III), VC and NbC (group V), have been investigated systematically using the first principles density functional theory (DFT). The full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange correlation has been used for the calculation of the total energy. The ground state properties, such as equilibrium lattice constant, bulk modulus, are computed and compared with theoretical and experimental data. The electronic and bonding patterns of the two groups of compounds have been analyzed quantitatively and compared with the available data. It is clear from band structures that all the four transition metal monocarbides are metallic in nature. Analysis of elastic constants reveals that the carbides of group III are ductile in nature while those of group V are brittle.

Figure optionsDownload as PowerPoint slideHighlights
► We have predicted the elastic constants for ScC and YC.
► The Debye temperatures for both TMCs are also predicted.
► Group III TMCs are predicted ductile while group V TMCs are brittle.
► The bonding properties are discussed due to different numbers of valence electrons.