PbCrO3高压诱导金属绝缘体相变过程中Pb的价态稳定性

（Stability of the Pb divalent state in insulating and metallic PbCrO3 ）

J. F. Zhao, S.-C. Haw, X. Wang, L. P. Cao, H.-J. Lin, C.-T. Chen, C. J. Sahle, A. Tanaka, J.-M. Chen, C. Q. Jin, Z. W. Hu, L. H. Tjeng

Phys. Rev. B 107, 24107 (2023)

Editor's Sugestion

We have investigated the local electronic structure of PbCrO3 by conducting x-ray absorption spectroscopy at the lead L3 and chromium L2,3 edges. We found that lead is divalent and chromium is charge-disproportionated into trivalent and hexavalent states at ambient pressures, explaining their insulating behavior. The high-resolution partial fluorescence yield of lead L3 spectra as a function of pressure revealed that the divalent state of lead ions remains unchanged at high pressures, when PbCrO3 changes into metal and its volume collapses by more than 10%. We infer that the insulator-to-metal transition does not involve a Pb-Cr charge transfer, but is associated with the conversion of Cr3+/Cr6+ charge-disproportionated states into a Cr4+ valence state.