We shed light on the interplay between structure and many-body effects relevant for itinerant ferromagnetism in LaAlO3/SrTiO3 heterostructures. The realistic correlated electronic structure is studied by means of the (spin-polarized) charge self-consistent combination of density functional theory (DFT) with dynamical mean-field theory (DMFT) beyond the realm of static correlation effects. Though many-body behavior is also active in the defect-free interface, a ferromagnetic instability occurs only with oxygen vacancies. A minimal Ti two-orbital eg-t2g description for the correlated subspace is derived. Magnetic order affected by quantum fluctuations builds up from effective double exchange between nearly-localized eg and mobile xy electrons.
@article{arxiv.1401.6105,
title = {Electron correlation and magnetism at the LaAlO$_3$/SrTiO$_3$ interface: A DFT+DMFT investigation},
author = {Frank Lechermann and Lewin Boehnke and Daniel Grieger and Christoph Piefke},
journal= {arXiv preprint arXiv:1401.6105},
year = {2014}
}