High-pressure synthesis of the $\mathrm{BiV}{\mathrm{O}}_3$ perovskite

We report the high-pressure, high-temperature synthesis of $\mathrm{BiV}{\mathrm{O}}_3$, a cubic perovskite that thus far has remained inaccessible under ambient pressure conditions. We created this material at $\sim 25$ GPa and 1500 K in a laser-heated diamond-anvil cell and recovered it to ambient pressure and temperature. Our synthetic approach circumvents the oxidative chemistry that, at ambient pressures, previously rendered the cubic $\mathrm{BiV}{\mathrm{O}}_3$ perovskite inaccessible. We find through density-functional theory calculations that this material is a unique metallic and antiferromagnetic transition-metal oxide.

Figure 1

Bragg peaks from the phase appear in the PXRD patterns after heating the Bi-V-O sample at high pressure $\left(\lambda =0.40663\AA \right)$. The temperature increases as indicated by the color of the patterns and by the colored arrow (red is high temperature). Stars mark the position of the peaks. During the heating process, the recrystallization of Bi leads to unphysical saturation features in select patterns.

Figure 2

Rietveld refinements at $\sim 21.1\mathrm{GPa}$ and at ambient pressure (left, $\lambda =0.40663\AA$) yield the structure of the phase to be the cubic $\mathrm{BiV}{\mathrm{O}}_3$ perovskite (right). Beneath the patterns, magenta tick marks denote peaks from the crystalline MgO, green marks denote peaks from the Bi(V) phase at 21.1 GPa, and blue marks denote peaks from the Bi(I) phase. The structure comprises Bi atoms, O atoms, and $\mathrm{V}{\mathrm{O}}_6$ moieties (represented as purple and red spheres and as blue octahedra, respectively).

Figure 3

DOS per formula unit for cubic $\mathrm{BiV}{\mathrm{O}}_3$ for the nonmagnetic case (top) and for the $A$-type antiferromagnetic ordering case (bottom) both show a nonzero DOS at the Fermi energy. Several van Hove singularities are present in the nonmagnetic DOS diagram above the Fermi energy. In the $A$-AFM DOS, the bands derived from the $d_{xy}$ orbital are no longer degenerate with those of $d_{yz}, d_{xz}$ symmetry owing to the spin order. The legend indicates the underlying orbital contributions to the total (gray) DOS. The dashed vertical line denotes the Fermi energy.