Works of separation for (0 0 0 1)ZnO|(1 1 1)ZrO2 interfaces: A first-principle study

Abstract

In-depth understanding of interfacial adhesive properties is required to access the long-term performance of substrate-film structures. The ZnO|ZrO2 (or ZnO|YSZ) interfaces are of widely interests in experiments, however, the study on their adhesive strength is rare. Works of separation for (0001)ZnO|(111)ZrO2 interfaces have been investigated by using density functional calculations. Four coherent interface configurations were calculated to clarify the influence of atom termination and stacking sequence on the interfacial strength. The coherent interface model indicates that the small values for the work of separation are attributed to the large lattice mismatch between two slabs. Among the four configurations, interface model with ZrZrO2-OZrO2⋯OZnOB-ZnZnOβ stacking sequence has the largest work of separation, followed by the model with ZrZrO2-OZrO2⋯ZnZnOβ-OZnOB stacking sequence. We also construct “semicoherent interface” models to investigate the effect of strain. The ZrZrO2-OZrO2⋯OZnOB-ZnZnOβ sequence brings in some direct electrostatically repulsive anion-anion interactions across the interface, which causes significant distortion for the interface, especially on ZnO slab. Based on the “semicoherent interface” model with ZrZrO2-OZrO2⋯ZnZnOβ-OZnOB sequence, we elucidate that the interfacial adhesive strength for (0001)ZnO|(111)ZrO2 interface is very low.