  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-Vis spectroscopy were used to reveal the structural
evolutions in RCrO3. The lattice parameter, Cr3+-O2--Cr3+ bond angle, and CrO6
octahedral distortions were found to strongly depend on the ionic radii of the
rare-earth element. First-principles 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
structure, and density of states (DOS) of RCrO3 were calculated. These provide
some insights into the electronic characteristics of the series of 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 the element R from both experiments and
calculations
