Existence of La-site antisite defects in [Formula: see text] ([Formula: see text], Fe, and Co) predicted with many-body diffusion quantum Monte Carlo

Tom Ichibha; Kayahan Saritas; Jaron T Krogel; Ye Luo; Paul R C Kent; Fernando A Reboredo

doi:10.1038/s41598-023-33578-1

Existence of La-site antisite defects in [Formula: see text] ([Formula: see text], Fe, and Co) predicted with many-body diffusion quantum Monte Carlo

Sci Rep. 2023 Apr 25;13(1):6703. doi: 10.1038/s41598-023-33578-1.

Authors

Tom Ichibha^{1

2}, Kayahan Saritas¹, Jaron T Krogel¹, Ye Luo³, Paul R C Kent⁴, Fernando A Reboredo¹

Affiliations

¹ Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA.
² School of Information Science, Japan Advanced Institute of Science and Technology, Asahidai 1-1, Nomi, Ishikawa 923-1292 Japan.
³ Computational Sciences Division, Argonne National Laboratory, Argonne, IL 60439 USA.
⁴ Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA.

Abstract

The properties of [Formula: see text] (M: 3d transition metal) perovskite crystals are significantly dependent on point defects, whether introduced accidentally or intentionally. The most studied defects in La-based perovskites are the oxygen vacancies and doping impurities on the La and M sites. Here, we identify that intrinsic antisite defects, the replacement of La by the transition metal, M, can be formed under M-rich and O-poor growth conditions, based on results of an accurate many-body ab initio approach. Our fixed-node diffusion Monte Carlo (FNDMC) calculations of [Formula: see text] ([Formula: see text], Fe, and Co) find that such antisite defects can have low formation energies and are magnetized. Complementary density functional theory (DFT)-based calculations show that Mn antisite defects in [Formula: see text] may cause the p-type electronic conductivity. These features could affect spintronics, redox catalysis, and other broad applications. Our bulk validation studies establish that FNDMC reproduces the antiferromagnetic state of [Formula: see text], whereas DFT with PBE (Perdew-Burke-Ernzerhof), SCAN (strongly constrained and appropriately normed), and the LDA+U (local density approximation with Coulomb U) functionals all favor ferromagnetic states, at variance with experiment.