PrVO under High Pressure: Effects on Structural, Optical and Electrical Properties
arXiv:2006.01299 · doi:10.1021/acs.inorgchem.0c02933
Abstract
In pursue of a systematic characterization of rare-earth vanadates under compression, in this work we present a multifaceted study of the phase behavior of zircon-type orthovanadate PrVO under high pressure conditions, up until 24 GPa. We have found that PrVO undergoes a zircon to monazite transition at around 6 GPa, confirming previous results found by Raman experiments. A second transition takes place above 14 GPa, to a BaWO-I--type structure. The zircon to monazite structural sequence is an irreversible first-order transition, accompanied by a volume collapse of about 9.6%. Monazite phase is thus a metastable polymorph of PrVO. The monazite-BaWO-II transition is found to be reversible instead and occurs with a similar volume change. Here we report and discuss the axial and bulk compressibility of all phases. We also compare our results with those for other rare-earth orthovanadates. Finally, by means of optical-absorption experiments and resistivity measurements we determined the effect of pressure on the electronic properties of PrVO. We found that the zircon-monazite transition produces a collapse of the band gap and an abrupt decrease of the resistivity. The physical reasons for this behavior are discussed. Density-functional-theory simulations support our conclusions.
34 pages,19 Figures (Including Supporting Information). Supporting Information. Submitted to Inorganic Chemistry