Fundamental properties of GaN(0001) films grown directly on Gd2O3(0001) platforms: Ab initio structural simulations

We present first-principles calculations to study the heterojunction between a wurtzite GaN(0001) film and a hexagonal Gd₂O₃(0001) substrate. We report that the most favorable Gd₂O₃(0001) surface is O terminated. Using the work of adhesion of isolated GaN and Gd₂O₃ slabs, our calculated interface energies suggest that the graphiticlike GaN films are fully relaxed at Gd₂O₃(0001) platforms, thereby leading to Ga-polarity in the GaN(0001) epitaxial film. Our findings agree with previously reported results.