2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/151659The strain induced by lattice mismatch at the interface is responsible for the different value of the band discontinuities observed recently for the AlN/GaN (AlN on GaN) and the GaN/AlN (GaN on AlN) polar (0001) interface. We present a first-principles calculation of valence band offsets, interface dipoles, strain-induced piezoelectric fields, relaxed geometric structure, and formation energies. Our results confirm the existence of a large forward-backward asymmetry for this interface.6 pages, 2 figures, MRS style (enclosed), to appear in MRS Proc. 448Materials Sciencetext