Piezoelectric AlN-based alloys, a first-principles study of structures, thermodynamics and properties.

Recent efforts have been made to find new piezoelectric materials offering adequate balance between piezoelectric response and other application-relevant properties. This push has lead to the investigation of various alloy systems with AlN-based alloys being the workhorse in piezoelectric resonators for wireless communications and related applications. This presentation focuses on our recent work on several of these alloys such as the pseudo-binary (SiC)(AlN) or the co-alloying of AlN with Sc and B.Using Density Functional Theory we model the structures of these systems at different compositions and different phases leading to the calculations of structural, mechanical and electronic properties such as lattice parameters, acoustic velocities, stiffness tensors or piezoelectric tensors. Our results show correlations and in some case de-correlations between the stiffness and the piezoelectric response and help understand the structure-property relationship in these systems with the objective of enabling composition identifications fulfilling application specific constraints.