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<p>A comprehensive DFT+U investigation of half-doped chromite perovskites (La<sub>0.5</sub>X<sub>0.5</sub>CrO<sub>3</sub> (X = Ba, Sr, Ca)) was performed to correlate lattice distortion with magnetic, electronic and optical responses. After full √2 × √2 × 2 super-cell optimisation, the pseudo-cubic lattice constant <i>a</i><sub>pc</sub> expands by +1.8% for Ba<sup>2+</sup> and contracts by –0.9% for Ca<sup>2+</sup>, shifting the Goldschmidt tolerance factor from 0.957 (Ca) to 1.016 (Ba). The concomitant Cr–O–Cr bond angle widens from 158° (Ca) to 170° (Ba), suppressing octahedral tilts. Total-energy calculations show that C-type antiferromagnetism remains the universal ground state, with stabilisation energies Δ<i>E</i> = 0.246–0.271 Ry (3.3–3.7 eV fu<sup>−1</sup>) and Cr local moments of 2.60 ± 0.03 μ<sub>B</sub>. Band-structure analysis reveals indirect-to-direct gap narrowing from 1.8 eV (Ba) → 1.1 eV (Sr) → 0.6 eV (Ca), reflected by static dielectric constants <i>ε</i><sub>0</sub> = 11.2, 14.6, 17.0 and refractive indices <i>n</i><sub>0</sub> = 3.3, 3.8, 4.1, respectively. These trends confirm that chemical pressure mediated by A-site radius systematically tunes bandwidth, exchange strength and optical edge, positioning Ba-rich members for visible/UV photonics, Sr for telecom-band devices and Ca for mid-IR spin-optoelectronics.</p>

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DFT+U investigation of structural and functional properties of doped LaCrO3 chromite perovskites

  • 期刊论文

  • 发表日期：

    2026年7月24日

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  • M Nasri,
  • J Khelifi,
  • Konstantin P Katin,
  • Elyor Berdimurodov,
  • Alisher Ishankulov

摘要

A comprehensive DFT+U investigation of half-doped chromite perovskites (La0.5X0.5CrO3 (X = Ba, Sr, Ca)) was performed to correlate lattice distortion with magnetic, electronic and optical responses. After full √2 × √2 × 2 super-cell optimisation, the pseudo-cubic lattice constant apc expands by +1.8% for Ba2+ and contracts by –0.9% for Ca2+, shifting the Goldschmidt tolerance factor from 0.957 (Ca) to 1.016 (Ba). The concomitant Cr–O–Cr bond angle widens from 158° (Ca) to 170° (Ba), suppressing octahedral tilts. Total-energy calculations show that C-type antiferromagnetism remains the universal ground state, with stabilisation energies ΔE = 0.246–0.271 Ry (3.3–3.7 eV fu−1) and Cr local moments of 2.60 ± 0.03 μB. Band-structure analysis reveals indirect-to-direct gap narrowing from 1.8 eV (Ba) → 1.1 eV (Sr) → 0.6 eV (Ca), reflected by static dielectric constants ε0 = 11.2, 14.6, 17.0 and refractive indices n0 = 3.3, 3.8, 4.1, respectively. These trends confirm that chemical pressure mediated by A-site radius systematically tunes bandwidth, exchange strength and optical edge, positioning Ba-rich members for visible/UV photonics, Sr for telecom-band devices and Ca for mid-IR spin-optoelectronics.