2024/05/25 by M. Schubert, Schubert, Mathias, Rafał Korlacki +3
Materials Science · #FOS: Physical sciences #Ga2O3 and related materials #Magnesium Oxide Properties and Applications #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2405.16307
openalex publication_date 2024/05/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this work we derive the state of strain or stress under symmetry conserving conditions in pseudomorphic lattices with monoclinic symmetry. We compare surface vectors across the template epitaxial layer interface and impose conditions of a stress free epitaxial layer. As a result, we demonstrate the existence, in theory, of exactly three possible unit cells which can establish onto a given template. We demonstrate this approach for a class of templates with (h0l) planes and β-(AlxGa1-x)2O3 on (h0l) β-Ga2O3. We discuss the effects of composition x and surface orientation onto the formation of three elastically stable unit cells, their strain and stress tensors, unit cell axes, unit cell volumes, lattice spacing, elastic potential energies, and stress free directions. The previous paradigm for epitaxial layer growth where the stress free direction is always perpendicular to the growing surface is not generally valid for low symmetry materials. In the example here, we find two possible competing domains with stress free direction oblique to the surface of the template for almost all planes (h0l). We calculate the band-to-band transitions for β-(Al0.1Ga0.9)2O3 on (h0l) β-Ga2O3 using the composition dependent deformation parameters and elastic coefficients reported prevoiously [Korlacki~et al. Phys. Rev. Appl.~18, 064019 (2022)].