Related Experiment Video
Updated: Jul 11, 2025
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Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
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Three-dimensional flat bands in pyrochlore metal CaNi2.
Joshua P Wakefield1, Mingu Kang1,2, Paul M Neves1
1Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
Nature
|November 8, 2023
Summary
Researchers discovered three-dimensional (3D) flat bands in CaNi2, a material with a nickel pyrochlore lattice. Chemical tuning of these bands to the Fermi level induced superconductivity and enhanced electron correlations.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Flat-band materials exhibit quenched kinetic energy, fostering electron correlation and emergent quantum phenomena.
- Recent advances have realized flat bands in 2D systems, but their existence in 3D networks remains an open experimental question.
Purpose of the Study:
- To investigate the existence and properties of three-dimensional (3D) flat bands in the C15 Laves phase metal CaNi2.
- To explore the potential for realizing novel quantum phenomena in 3D flat-band systems.
Main Methods:
- Utilized angle-resolved photoemission spectroscopy (ARPES) to probe electronic band structure.
- Employed chemical tuning to modify the electronic properties of CaNi2.
- Investigated electronic correlations and superconductivity through experimental measurements.
Main Results:
- Observed a dispersionless band across the 3D Brillouin zone, identified as the predicted pyrochlore flat band.
- Discovered two additional flat bands resulting from multi-orbital interference of Ni d-electrons.
- Demonstrated that tuning the flat-band manifold to the Fermi level enhances electronic correlations and induces superconductivity.
Conclusions:
- CaNi2 hosts a unique 3D topological flat band and additional multi-orbital flat bands.
- Chemical tuning provides a pathway to engineer correlated states and superconductivity in 3D flat-band systems.
- This work extends the concept of intrinsic band flatness to 3D, opening avenues for higher-dimensional quantum phenomena.
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