Using {\it ab initio} density functional theory we explore the behavior of thin layers of metallic d4 SrFeO3 confined between the d0 dielectric SrTiO3 in a superlattice geometry. We find the presence of insulating SrTiO3 spacer layers strongly affects the electronic properties of SrFeO3: For single SrFeO3 layers constrained to their bulk cubic structure, the Fermi surface is two-dimensional, nested and resembles the hole-doped superconducting cuprates. A Jahn-Teller instability couples to an octahedral tilt mode, however, to remove this degeneracy resulting in insulating superlattices.
@article{arxiv.0908.3502,
title = {Electron-lattice instabilities suppress cuprate-like electronic structures in SrFeO$_3$/SrTiO$_3$ superlattices},
author = {James M. Rondinelli and Nicola A. Spaldin},
journal= {arXiv preprint arXiv:0908.3502},
year = {2010}
}