New Publication in Advanced Science: Uncovering the Earliest Stages of Phase Separation in Functional Oxide Thin Films

Published: July 9, 2026

How metallic nanoparticles emerge from oxide materials is a key question for the development of next-generation catalysts, energy conversion devices, and electronic materials. Researchers from PGI-7, together with their collaborators, have now uncovered that phase separation in exsolution-active Ni-doped and (Nb,Ni)-co-doped SrTiO₃ thin films begins much earlier than previously assumed—upon the first monolayer.

By combining scanning tunnelling microscopy and spectroscopy (STM/S) with scanning transmission electron microscopy (STEM), the team identified Ni-rich defect clusters that form already during island nucleation. The study further shows that these Ni in the clusters, together with Ni atoms in the perovskite lattice, give rise to metallic nanoparticle exsolution through two distinct pathways.

The findings provide fundamental insights into dopant induced phase separation in complex oxide materials. A better understanding of these atomic-scale processes opens new opportunities to precisely tailor exsolution-based materials for catalytic, electronic, and energy-related applications.

The results have been published in Advanced Science:
Y.-P. Liu, M. L. Weber, D. Jennings, L. L. Rusevich, E. Kotomin, R. Timm, F. Gunkel, and R. Dittmann, Partial Phase-Separation in the Initial Growth Stage of Exsolution-Active SrTi₀.₉₅₋ₓNi₀.₀₅NbₓO₃₋δ Thin Films, Advanced Science (2026), e76812.
https://doi.org/10.1002/advs.76812

Internal Contacts (FZJ)

Yen-Po Liu

Postdoctoral researcher

• Peter Grünberg Institute (PGI)
• Electronic Materials (PGI-7)

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Dr. Felix Gunkel

Senior Researcher / Group leader Associate Professor, University of Twente (Guest @ IMS)

• Peter Grünberg Institute (PGI)
• Electronic Materials (PGI-7)

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Prof. Dr. Regina Dittmann

Director Electronic Materials (PGI-7)

• Peter Grünberg Institute (PGI)
• Electronic Materials (PGI-7)

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