At just four nanometers thick, this metal starts behaving in a way physicists did not expect

Key Points:

• Researchers at the University of Minnesota Twin Cities have discovered that interfacial polarization can tune the surface work function of metallic ruthenium dioxide (RuO2) by over 1 electron volt by adjusting film thickness at the nanometer scale.
• The study reveals that stabilizing polarization in a metallic system through interface design enables control of electronic properties, challenging the traditional view that polarization is limited to insulators or ferroelectrics.
• The most significant effect occurs when the metal layer is about 4 nanometers thick, where a transition from a "stretched" to a "relaxed" atomic state directly influences the metal's electrical behavior.
• This discovery, detailed in Nature Communications, has potential applications in the development of advanced electronic, catalytic, and quantum devices.
• The research was a collaborative effort involving institutions including the University of Minnesota, MIT, Texas A&M University, and Gwangju Institute of Science and Technology.