Design of a d(1)-analogue of cuprates: Sr(2)VO(4) and Ba(2)VO(4) under pressure

By means of a combination of the local density approximation and dynamical mean field theory (LDA + DMFT), we study the possibility of making a d(1) analogue of d(9) cuprates on the basis of Sr(2)VO(4). We calculate the electronic structure of Sr(2)VO(4) under pressure, and show that while the material is a 1/6-filled three-band system at ambient pressure with a small level splitting between the d(xy)- and d(yz/zx)-bands, an orbital polarization occurs under sufficiently high uniaxial pressure in the c-direction. While all energy scales are relatively small, the electronic structure of Sr(2)VO(4) under pressure is similar to that of La(2)CuO(4); it is a two-dimensional half-filled single-band system which has, relative to the nearest neighbour hopping, a similar Coulomb repulsion and next-nearest neighbour hopping. We also study the effect of substituting Sr by Ba, i.e., chemical pressure, and show that the pressure needed for the orbital polarization is considerably reduced.