The structural, elastic and electronic properties of A2C2 (A = Li, Na, K, Rb and Cs): First-principles calculations

The structural, elastic and electronic properties of A 2 C 2 (A = Li , Na , K , Rb and Cs ) at zero temperature were investigated by first-principles total energy calculations. The optimized equilibrium structural parameters agree well with available experimental values. Elastic constants, bulk modulus, Young's modulus and Poissons ratio were given. All the structures studied are stable mechanically and all stable A 2 C 2 studied has strong compressibility, which originates from weak Coulomb repulsion between metal atoms and carbon atoms. The electronic structure calculations show that binary alkali metal carbides studied here are insulators.