Multiband Optical Absorption Controlled by Lattice Strain in Thin-FilmLaCrO3

Abstract

Experimental measurements and ab initio modeling of the optical transitions in strained G-type antiferromagnetic LaCrO(3) resolve two decades of debate regarding the magnitude of the band gap and the character of the optical absorption spectrum in the visible-to-ultraviolet (up to ∼5 eV) range in this material. Using time-dependent density functional theory and accounting for thermal disorder effects, we demonstrate that the four most prominent low-energy absorption features are due to intra-Cr t(2g)-e(g) (2.7, 3.6 eV), inter-Cr t(2g)-t(2g) (4.4 eV), and interion O 2p-Cr 3d (from ∼5 eV) transitions and show that the excitation energies of the latter type can be strongly affected by the lattice strain.

Device Performance of the Mott InsulatorLaVO3as a Photovoltaic Material

“…After a slight decrease at approximately 3 eV, the absorption increases again in the UV range. The absorption spectrum of LVO can be well fitted by five broadened Gaussian peaks [37,38], and the peak positions are summarized in Table I. As shown in the inset of Fig.…”

Improved description of perovskite oxide crystal structure and electronic properties using self-consistent Hubbard U corrections from ACBN0

“…At the time there was no additional experimental evidence clarifying the electronic structure of LaCrO 3 , but in 2013 Sushko et al 68 reported experimental measurements coupled with embedded cluster time-dependent DFT that discerned the multiple optical transitions present in this material. Spectroscopic ellipsometry revealed onset of absorption features near 2.3 eV and 3.2 eV, occurring before the large 5 eV optical absorption onset.…”

Perovskite Sr‐Doped LaCrO3 as a New p‐Type Transparent Conducting Oxide

“…Bulk LCO is an orthorhombic perovskite (space group Pbnm ) with lattice parameters a = 5.513 Å, b = 5.476 Å, c = 7.759 Å, and a pseudocubic parameter a = 3.885 Å (see schematic model in Figure S2a in the Supporting Information). Sushko et al have shown that the lowest energy excitation in LCO results from a t 2g 3 → e g 0 transition at ≈2.8 eV that is formally dipole forbidden. The O 2 p → Cr 3 d charge‐transfer excitation shows the strongest optical absorption and falls at ≈4.6 eV.…”

“…Based on time‐dependent density functional theory calculations of the excitation energies and corresponding intensities, feature A is assigned to the dipole forbidden t 2g 3 → e g 0 excitation, as shown schematically in Figure c. The extrapolated forbidden bandgaps are plotted in the inset of Figure a.…”