Pressure-induced cation-cation bonding inV2O3

Abstract

A pressure-induced phase transition, associated with the formation of cation-cation bonding, occurs in ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$ by combining synchrotron x-ray diffraction in a diamond anvil cell and ab initio evolutionary calculations. The high-pressure phase has a monoclinic structure with a $C2/c$ space group, and it is both energetically and dynamically stable at pressures above 47 GPa to at least 105 GPa. This phase transition can be viewed as a two-dimensional Peierls-like distortion, where the cation-cation dimer chains are connected along the $c$ axis of the monoclinic cell. This finding provides insights into the interplay of electron correlation and lattice distortion in ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$, and it may also help to understand novel properties of other early transition-metal oxides.