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Minnesota Team Shifts RuO2 Work Function Over 1 eV

4/28/2026

Summary

Minnesota Researchers Shift

University of Minnesota Twin Cities researchers tuned the RuO2/TiO2 work function by over 1 eV.
The shift appears at about 4 nm RuO2 thickness, where strain creates polarization.
Bharat Jalan and Seung Gyo Jeong visualized picometre ion displacements forming dipoles with electron ptychography.
U.S. Department of Energy (DOE) and Air Force Office of Scientific Research funded work, which appeared in Nature Communications on 9 February 2026 and could aid semiconductors, catalysis and quantum devices.

Summary

Jalan Creates PolarMetal

The study overturns the belief that free-electron screening blocks internal electric fields in metals by showing a polarized state can exist.
Mechanical strain applied at an atomically engineered RuO2 interface stabilizes this polarized state despite the material’s metallic conductivity.
Professor Bharat Jalan of the University of Minnesota called the result a “near-contradiction” and said it creates a “polar metal” concept that could merge conductivity with ferroelectric-like behavior.

Summary

Researchers Detect Dipoles

Researchers used multislice electron ptychography in a scanning transmission electron microscope to reconstruct atomic positions.
The technique imaged heavy metal ions and lighter oxygen atoms at the interface with sub-picometre precision.
Measured displacements of only a few picometres revealed electric dipoles in the metal.
The observation demonstrates that electron ptychography can capture picometre-scale ionic shifts, marking the first direct detection of polar dipoles in a conducting metal.

History

Historical Context

Building on Anderson and Blount’s 1965 prediction of ferroelectric metals and the 2013 University of Tokyo discovery that LiOsO3 becomes polar while remaining metallic at 140 K, University of Minnesota researchers Bharat Jalan and Seung Gyo Jeong have now engineered RuO2/TiO2 interfaces that exhibit the same polar-metal behavior, a step toward quantum devices.

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Minnesota Researchers Shift

University of Minnesota Twin Cities researchers tuned the RuO2/TiO2 work function by over 1 eV.
The shift appears at about 4 nm RuO2 thickness, where strain creates polarization.
Bharat Jalan and Seung Gyo Jeong visualized picometre ion displacements forming dipoles with electron ptychography.
U.S. Department of Energy (DOE) and Air Force Office of Scientific Research funded work, which appeared in Nature Communications on 9 February 2026 and could aid semiconductors, catalysis and quantum devices.

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