Structural and electronic properties of rare-earth chromites: A computational and experimental study

In this work, the structural, optical, and electronic properties of rare-earth perovskites of the general formula RCrO3, where R represents the rare-earth Gd, Tb, Dy, Ho, Er, and Tm, have been studied in detail. These compounds were synthesized through a facile citrate route. X-ray diffraction, Raman spectroscopy, and UV-Visible spectroscopy were utilized to reveal the structural evolutions in RCrO3. The lattice parameters, Cr3+-O2-Cr3+ bond angle, and CrO6 octahedral distortions were found to strongly depend on the ionic radii of R. Firstprinciples calculations based on density-functional theory within the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) and strongly constrained and appropriately normed (SCAN) meta-GGA were also employed to calculate the structural and electronic properties of RCrO3. The ground-state energy, lattice constants, electronic structures, and density of states of RCrO3 were calculated. These provide some insights into the electronic characteristics of the RCrO3 compounds. The calculated values of lattice parameters and band gaps with Hubbard U correction (SCAN + U) agree well with values measured experimentally and show more accuracy in predicting the ground-state crystal structure and band structure compared to PBE + U approximation. The band gap of RCrO3 is found to be independent of the ionic radii of R from both experiments and calculations.

Automated summary

This study investigates the structural, optical, and electronic properties of rare-earth perovskites RCrO3 through experiments and calculations. The results show that the structural parameters and band gaps are dependent on the ionic radii of R, and the modified calculation method is more accurate than the traditional one.