Strontium Titanate Capping Layers as Kinetic Regulators of Redox Phase Transitions in Oxide Heterostructures
Abstract
Oxide capping layers are widely used to protect and stabilize thin-film heterostructures, yet their role in governing phase-transition kinetics remains largely unexplored. Here, we uncover the kinetic function of few-nanometer-thick SrTiO3 (STO) capping layers in controlling oxidation and reduction processes, using real-time in situ optical spectroscopic ellipsometry. We show that oxygen diffusion through the nanoscale capping layer constitutes the rate-limiting step, giving rise to diffusion-controlled phase transitions in the underlying materials. As a result, both capping-layer thickness and oxygen partial pressure provide effective handles to tune phase transition temperatures. Quantitative analysis yields an activation energy of EA = 0.64 ±0.06 eV for oxygen diffusion through STO, highlighting its suitability for precise control of redox reactions in diverse material systems. These results establish oxide capping layers as active kinetic regulators of redox-driven phase transitions and offer a general framework for engineering redox dynamics in complex oxide heterostructures.
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BibTeX
@misc{abdollahi2026strontium,
title = {{Strontium Titanate Capping Layers as Kinetic Regulators of Redox Phase Transitions in Oxide Heterostructures}},
author = {Pooya Abdollahi and Woo Jin Kim and Keaghan Knight and Harold Y. Hwang and Ambrose Seo},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.31871},
eprint = {2610.31871},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.31871},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Strontium Titanate Capping Layers as Kinetic Regulators of Redox Phase Transitions in Oxide Heterostructures
AU - Pooya Abdollahi
AU - Woo Jin Kim
AU - Keaghan Knight
AU - Harold Y. Hwang
AU - Ambrose Seo
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.31871
UR - https://arxiv.org/abs/2610.31871
AB - Oxide capping layers are widely used to protect and stabilize thin-film heterostructures, yet their role in governing phase-transition kinetics remains largely unexplored. Here, we uncover the kinetic function of few-nanometer-thick SrTiO_3 (STO) capping layers in controlling oxidation and reduction processes, using real-time in situ optical spectroscopic ellipsometry. We show that oxygen diffusion through the nanoscale capping layer constitutes the rate-limiting step, giving rise to diffusion-controlled phase transitions in the underlying materials. As a result, both capping-layer thickness and oxygen partial pressure provide effective handles to tune phase transition temperatures. Quantitative analysis yields an activation energy of E_A = 0.64 ±0.06 eV for oxygen diffusion through STO, highlighting its suitability for precise control of redox reactions in diverse material systems. These results establish oxide capping layers as active kinetic regulators of redox-driven phase transitions and offer a general framework for engineering redox dynamics in complex oxide heterostructures.
ER -