New phase boundary in highly correlated, barely metallicV2O3

We compare the magnetic and transport properties of the low-temperature metal in nonstoichiometric and compressed vanadium sesquioxide. Antiferromagnetic order is robust for the full range of vanadium vacancy concentrations, but it can be suppressed with modest hydrostatic pressures. The temperature-pressure phase diagram for ${\mathrm{V}}_2$ ${\mathrm{O}}_3$ thus includes a new T=0 boundary between antiferromagnetic and paramagnetic metals. Furthermore, analysis of the T→0 diffusive metallic conductivity at the approach to the insulator-metal transition indicates a different role for correlations depending upon the means employed to effect the transition.