Structural, electronic and mechanical properties of Imma-carbon

A theoretical investigation on mechanical and electronic properties of Imma-carbon was performed by employing first-principles calculations based on the density functional theory. The stability at ambient condition is approved by phonon dispersion and elastic constants calculations. The analysis of elastic anisotropy and hardness anisotropy shows that Imma-carbon is nearly mechanical isotropy. The large elastic constants and ideal strength indicate Imma-carbon is a potential superhard material. Ideal strength studies show that (010) plane is the easy cleavage plane for Imma-carbon, and the cleavage mechanism was discussed in detail. The calculated band structure is a direct band gap semiconductor with 2.97 eV gap at Γ-point.