Energetic, mechanical and dynamical stability, electronic and bonding properties of new antiperovskite nitrides Y3AlN and Y3GaN: DFT and QTAIM investigation

Abstract

New intermetallic antiperovskites (Y3AlN and Y3GaN) 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 Cij 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 Y3AlN and Y3GaN can be synthesized experimentally. Vibrational behaviours have been studied in detail. This study has shown that Y3AlN and Y3GaN 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.