We study Sr2(Ba2)VO4 under high pressure by means of the local density approximation + dynamical mean field theory method. While Sr2VO4 is a 1/6-filling three-band system at ambient pressure with a small level splitting between the dxy- and dyz/zx-bands, we show that an orbital polarization occurs under uniaxial pressure, resulting in dramatic changes of the magnetic, optical, and transport properties. When pressure is applied in the c-direction, a d1 analog of d9 cuprates is realized, making Sr2(Ba2)VO4 a possible candidate for a d1 superconductor. Experimentally, this uniaxial pressure can be realized by growing Ba2VO4 on a substrate with lattice constant 4.1-4.2 \AA.
@article{arxiv.cond-mat/0611698,
title = {Sr$_2$(Ba$_2$)VO$_4$ under pressure -- an orbital switch and potential $d^1$ superconductor},
author = {R. Arita and A. Yamasaki and K. Held and J. Matsuno and K. Kuroki},
journal= {arXiv preprint arXiv:cond-mat/0611698},
year = {2009}
}