Energetic, mechanical and dynamical stability, electronic and bonding properties of new antiperovskite nitrides Y 3 AlN and Y 3 GaN: DFT and QTAIM investigation

New intermetallic antiperovskites (Y 3 AlN and Y 3 GaN) have been studied with the aim of confirming the possibility of their synthesis. To ensure the accuracy of the results, two calculation methods have been used (FP-LAPW and PW-PP). First, the two methods gave similar and negative formation energy values, which confirms their energetic stability. Elastic stiffness constants C ij have shown that these materials are mechanically stable. Phonon dispersion curves have confirmed their dynamical stability, and from all the above, it is confirmed that Y 3 AlN and Y 3 GaN can be synthesized experimentally. Vibrational behaviours have been studied in detail. This study has shown that Y 3 AlN and Y 3 GaN are metallic, this behaviour is mainly due to Y-d states. Using QTAIM, four bonds were found to be present. By analysing the characteristics of BCPs, it was found that (Al,Ga)-(Al,Ga) and (Al,Ga)-Y bonds are metallic, while (Al,Ga)-N and Y–N have been classified as dative.