Programme

P.5 -- Posters, VCTP-51

Date: Tuesday, 4 August 2026

Time: 09:30 - 10:30

First-principles elucidation of hydrogen insertion in Sr3Co3O8 in Grenier Phase

Truong Ngoc Diep,(1) Thanh Ngoc Pham (2,3)

(1) College of Natural Sciences, Can Tho University, Can Tho City, Viet Nam (2) An Giang University, An Giang, Vietnam (3) Vietnam National Univeristy- Ho Chi Minh city, Ho Chi Minh, Vietnam

Recently, oxygen-deficient transition-metal oxides with the Grenier-phase structure have attracted significant attention because they combine key structural and functional characteristics of both perovskite and brownmillerite oxides. This unique framework offers opportunities for tuning ionic transport, electronic properties, and topotactic phase transitions [1-3]. However, the atomic-scale mechanisms and electronic consequences of hydrogen insertion in Grenier-phase oxides remain poorly understood. In this work, we investigate the structural and electronic properties of Sr_3Co_3O_8 and its hydrogenated phases using first-principles density functional theory calculations. We find that the polar and antipolar phases are nearly degenerate in energy, suggesting that Sr_3Co_3O_8 exhibits a polar instability and may exhibit switchable structural distortions under external stimuli. Hydrogen insertion is thermodynamically favorable and proceeds through O–H bond formation, accompanied by significant charge redistribution and modifications of the Co–O bonding network. The resulting electronic-structure changes provide insights into the stabilization mechanism of the hydrogenated phase and the role of hydrogen in tuning the properties of Grenier-phase cobalt oxides. These findings will be presented and discussed at the conference. [1] J. Zhang et al. Nat. Mater. 23, 912-919 (2024) [2] Y Shin, J Liang, G. Yu, C. Leighton, G. Galli, ACS Appl. Mater. Interfaces 17, 15603-15612 (2025) [3] Y. Isoda, T. N.Pham, R. Aso, S. Nakamizo, T. Majima, S. Hosokawa, K. Nitta, Y. Morikawa, Y. Shimakawa, D. Kan, Nat Comm, 16, 56 (2025)

Presenter: Pham Ngoc Thanh