Structural and electronic properties of M2InC (M = Ti, Zr, and Hf)

Using pseudopotential plane waves approach based on density functional theory within the generalized gradient approximation, we have performed a study of the structural and electronic properties of selected M2InC compounds belonging to the so-called MAX phases, with M=Ti, Zr, and Hf. The calculated equilibrium lattice parameters are in good agreement with the experimental values. The effect of high pressures, up to 50 GPa, on the lattice constants shows that the contractions along the cc-axis were higher than along aa axis. The elastic constants are calculated using the static finite strain technique. The analysis of the band structure, density of states and electron charge density show that these compounds are electrical conductors, with a strong directional bonding between M and C atoms assured by the hybridisation of M-atom dd states with C-atom pp states. The hydrostatic pressure effect on the bond lengths showed that strengthens of M–C and M–In bonds decreases in the sequence Hf2InC→→ Ti2InC→→ Zr2InC.