Twisted graphene study reveals superconductivity control via environment
Researchers at Ohio State University have found that superconductivity can be switched on and off by changing the material’s surrounding environment. The study, published in Nature Physics, used twisted bilayer graphene combined with strontium titanate, a synthetic diamond-like material. By tuning how electrons interact with their surroundings, the team strengthened or weakened those interactions to control superconductivity. The behavior defied conventional superconductor rules: increasing adjustments weakened superconductivity instead of strengthening it. Lead author Chun Ning Lau said the work provides a path toward a new type of physics mechanism. Co-author Xueshi Gao noted the result can help people better understand superconductivity in future work. The team expects the findings to become useful for many experiments and material systems. Researchers cautioned that this is an early step and plan further experiments.
What’s reported
The study was led by Chun Ning (Jeanie) Lau, a physics professor at The Ohio State University.
The material used was twisted bilayer graphene combined with strontium titanate.
Researchers could switch superconductivity on and off by tuning electron interactions via the material’s environment.
As adjustments increased, superconductivity became weaker, contrary to conventional superconductors where reducing repulsive forces strengthens superconductivity.
The findings were published in Nature Physics.
The research was supported by the Department of Energy and the National Science Foundation.
Co-authors from Ohio State included Aatmaj Rajesh, Emilio Codecido, Daria Sharifi, Zheneng Zhang, Youwei Liu, and Marc Bockrath.
Collaborators included Alejandro Jimeno-Pozo, Pierre Pantaleon, Paco Guinea (Imdea Nanoscience, Spain), and Kenji Watanabe and Takashi Taniguchi (National Institute for Materials Science, Japan).
Open questions
The article does not explain precisely how the environment affects electron interactions. The mechanism of superconductivity in the twisted bilayer graphene system remains not well understood.
Key figures
Chun Ning (Jeanie) Lau, physics professor at Ohio State University
Xueshi Gao, PhD student in physics at Ohio State University and lead author
Aatmaj Rajesh, Emilio Codecido, Daria Sharifi, Zheneng Zhang, Youwei Liu, Marc Bockrath (Ohio State co-authors)
Alejandro Jimeno-Pozo, Pierre Pantaleon, Paco Guinea (Imdea Nanoscience, Spain)
Kenji Watanabe, Takashi Taniguchi (National Institute for Materials Science, Japan)
Sources: ScienceDaily
