Ab initio calculation insights into the structural, elastic and mechanical properties of high- k dielectric gadolinium oxide (Gd 2 O 3 )

It is necessary to have insights into the structural, elastic, and mechanical behaviors of material among many other factors for integrating it to devices for large-scale technological applications. First-principles calculations based on density functional theory (DFT) were used to study the structural, elastic and mechanical properties of gadolinium oxide (Gd 2 O 3 ) at the level of generalized gradient approximations in different polymorphic phases. All calculations were performed with the projector-augmented wave method within the framework of DFT in cubic (bixbyite), hexagonal, monoclinic as well as tetragonal phases. The results of lattice constants and different elastic moduli with generalized gradient approximation are found to be reliable. This study also reveals that the bulk modulus for all the phases of Gd 2 O 3 lies around 100 GPa suggesting that the considered phases are soft in nature and can simply be deposited as better quality thin films, which is important for thin-film based applications. Elastic properties such as bulk and shear elastic moduli, mechanical stability and elastic anisotropy were calculated that is not available in the literature. In this observation, Gd 2 O 3 exhibited ductile nature and mechanically stable behavior in all polymorphic phases.