Emergence of a potential charge-disproportionated insulating state in SrCrO 3

• Published in: Physical review research 2024-06, Vol.6 (2), Article 023240
• Main Authors: Carta, Alberto, Panda, Anwesha, Ederer, Claude
• Format: Article
• Language: English
• ISSN: 2643-1564; 2643-1564
• DOI: 10.1103/PhysRevResearch.6.023240

We use a combination of density functional theory (DFT) and dynamical mean-field theory (DMFT) to investigate the potential emergence of a charge-disproportionated insulating phase in SrCrO 3 , whereby the Cr cations disproportionate according to 3 Cr 4 + → 2 Cr 3 + + Cr 6 + and arrange in ordered planes perpendicular to the cubic [111] direction. We show that the charge disproportionation couples to a structural distortion where the oxygen octahedra around the nominal Cr 6 + sites contract, while the octahedra surrounding the Cr 3 + sites expand and distort. Our results indicate that the charge-disproportionated phase can be stabilized for realistic values of the Hubbard U and Hund's J parameters, but this requires a scaling of the DFT+DMFT double-counting correction by at least 35%. The disproportionated state can also be stabilized in DFT + U calculations for a specific magnetic configuration with antiparallel magnetic moments on adjacent Cr 3 + sites and no magnetic moment on the Cr 6 + sites. While this phase is higher in energy than other magnetic states that can arise in SrCrO 3 , the presence of an energy minimum suggests that the charge-disproportionated state represents a metastable state of SrCrO 3 .