Structural, elastic constants, hardness, and optical properties of pyritetype dinitrides (CN _{2}, SiN _{2}, GeN _{2})
Abstract
The crystal structures, band structures, elastic constants, hardness, and optical properties of pyritetype dinitrides (CN _{2}, SiN _{2}, and GeN _{2}) are obtained from the density functional theory using the planewave pseudopotential (PWP) method within the local density and generalized gradient approximations. The formation enthalpies for AN _{2} (A=C, Si, and Ge) compounds suggest the three structures that are stable. The calculated band structures show the indirect gaps ( ΓR) in CN _{2}, SiN _{2}, and GeN _{2}. The intrinsic hardnesses of AN _{2} (A=C, Si, and Ge ) compounds are calculated. Our results show that the cubic CN _{2} and SiN _{2} are superhard materials. Furthermore, we studied the optical properties such as the complex dielectric function and the electron energy loss spectra.
 Publication:

Physica B Condensed Matter
 Pub Date:
 April 2011
 DOI:
 10.1016/j.physb.2011.01.003
 Bibcode:
 2011PhyB..406.1357D