Strain-stabilized interfacial polarization tunes work function over 1 eV in RuO2/TiO2 heterostructures
Interfacial polarization - charge accumulation at the heterointerface - is a well-established tool in semiconductors, but its influence in metals remains unexplored. Here, we demonstrate that interfacial polarization can robustly modulate surface work function in metallic rutile RuO<sub>2</sub> layers in epitaxial RuO<sub>2</sub>/TiO<sub>2</sub> heterostructures grown by hybrid molecular beam epitaxy. Using multislice electron ptychography, we directly visualize polar displacements of transition metal ions relative to oxygen octahedra near the interface, despite the conductive nature of RuO<sub>2</sub>. This interfacial polarization enables over 1 eV modulation of the RuO<sub>2</sub> work function, controlled by small thickness variations (2-3 nm), as measured by Kelvin probe force microscopy, with a critical thickness of ~4 nm - corresponding to the transition from fully-strained to relaxed film. These results establish interfacial polarization as a powerful route to control electronic properties in metals and have implications for designing tunable electronic, catalytic, and quantum devices through interfacial control in polar metallic systems.
Authors
- In Hyeok Choi (ORCID: https://orcid.org/0009-0009-6067-6196)
- Matthew Neurock (ORCID: https://orcid.org/0000-0003-1458-7837)
- Seung Gyo Jeong (ORCID: https://orcid.org/0000-0002-2504-3571)
- Anand Santhosh (ORCID: https://orcid.org/0009-0002-5805-4004)
- Mengru Jin (ORCID: https://orcid.org/0000-0002-2925-9572)
- Qing Yun Tu
- Kelsey A. Stoerzinger (ORCID: https://orcid.org/0000-0002-3431-8290)
- Rashmi Choudhary (ORCID: https://orcid.org/0000-0002-3558-1277)
- Low Tony
- B. N. Lin
- Bharat Jalan
- Sreejith Nair
- Juhi Parikh
- Seungjun Lee
- James M. LeBeau
- Zhifei Yang
- Jong Woo Lee
Institutions
- University of Minnesota (US)
- University of Minnesota System (US)
- Gwangju Institute of Science and Technology (KR)
- Twin Cities Orthopedics (US)
- Massachusetts Institute of Technology (US)
- Texas A&M University (US)
Publication Details
- Journal
- Nature Communications
- Published
- 2026-02-09
- DOI
- https://doi.org/10.1038/s41467-026-69200-x
- Primary Topic
- Electronic and Structural Properties of Oxides
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- U.S. Department of Energy
- University of Minnesota
- National Research Foundation
- National Research Foundation of Korea
- Ministry of Science and ICT, South Korea
- Materials Research Science and Engineering Center, Harvard University
- Multidisciplinary University Research Initiative
- Division of Materials Research
- Division of Civil, Mechanical and Manufacturing Innovation
- Air Force Office of Scientific Research