Ab initio electronic structure studies of prototypical polar interfaces of wurtzite III-V nitrides show that large uniform electric fields exist in epitaxial nitride overlayers, due to the discontinuity across the interface of the macroscopic polarization of the constituent materials. Polarization fields forbid a standard evaluation of band offsets and formation energies: using new techniques, we find a large forward-backward asymmetry of the offset (0.2 eV for AlN/GaN (0001), 0.85 eV for GaN/AlN (0001)), and tiny interface formation energies.
@article{arxiv.cond-mat/9712245,
title = {Macroscopic polarization and band offsets at nitride heterojunctions},
author = {Fabio Bernardini and Vincenzo Fiorentini},
journal= {arXiv preprint arXiv:cond-mat/9712245},
year = {2009}
}