Pressure-Induced Charge-Order Melting and Reentrant Charge Carrier Localization in the Mixed-Valent Pb3Rh7O15.

The mixed-valent PbRhOundergoes a Verwey-type transition atK, below which the development of Rh/Rhcharge order induces an abrupt conductor-to-insulator transition in resistivity. Here we investigate the effect of pressure on the Verwey-type transition of PbRhOby measuring its electrical resistivity under hydrostatic pressures up to 8 GPa with a cubic anvil cell apparatus. We find that the application of high pressure can suppress the Verwey-type transition around 3 GPa, above which a metallic state is realized at temperatures below ∼70 K, suggesting the melting of charge order by pressure. Interestingly, the low-temperature metallic region shrinks gradually upon further increasing pressure and disappears completely at P > 7 GPa, which indicates that the charge carriers in PbRhOundergo a reentrant localization under higher pressures. We have constructed a temperature-pressure phase diagram for PbRhOand compared to that of FeO , showing an archetype Verwey transition. [ABSTRACT FROM AUTHOR]