First-principles DFT+\emph{U} study of structural and electronic properties of PbCrO$_{3}$

TL;DR

This study uses first-principles DFT+U calculations to explore the structural, electronic, and magnetic properties of PbCrO₃ and related compounds, aligning well with experimental data and revealing bonding and volume characteristics.

Contribution

It provides a systematic DFT+U analysis of PbCrO₃, clarifying its magnetic states, bonding nature, and volume effects, which were not fully understood before.

Findings

Good agreement with experimental lattice constants and bulk moduli.

Bonding exhibits covalent character with decreasing ionicity in Cr-rich compounds.

Large volume and compressibility linked to CrPbO₃ content and octahedral transitions.

Abstract

We have performed a systematic first-principles investigation to calculate the structural, electronic, and magnetic properties of PbCrO$_{3}$, CrPbO$_{3}$ as well as their equiproportional combination. The local density approximation (LDA)$+U$ and the generalized gradient approximation$+U$ theoretical formalisms have been used to account for the strong on-site Coulomb repulsion among the localized Cr 3d electrons. By choosing the Hubbard \emph{U} parameter around 4 eV, ferromagnetic, and/or antiferromagnetic ground states can be achieved and our calculated lattice constants, bulk moduli, and equation of states are in good agreement with recent experiments [W. Xiao \emph{et al.}, PNAS \textbf{107}, 14026 (2010)]. The bonding nature of B$-$O bonds in these ABO$_{3}$ compounds exhibit evident covalent character and our electron transferring study indicates that the ionicity shows decreasing trend with increasing fraction of CrO$_{6/2}$ octahedron within the PbCrO$_{3}$-CrPbO$_{3}$ random compounds. The lengthes of B$-$O bonds determine their lattice parameters, thus, clearly indicates that the abnormally large volume and compressibility is due to the contain of CrPbO$_{3}$ in the experimental sample and the transition of PbO$_{6/2}$ octahedron to CrO$_{6/2}$ upon compression.