In twisted graphene, some electrons are heavier than others (original) (raw)

When two graphene layers are twisted at a ‘magic angle’, their electrons can behave as both heavy and light particles, depending on momentum.

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  1. Hongyun Zhang
    1. Hongyun Zhang is in the Department of Physics, Tsinghua University, Beijing 100084, China, the Beijing Tsinghua Frontier Interdisciplinary Innovation Research Institute, Beijing, China, and the Advanced Institute for Materials Research, Tohoku University, Sendai, Japan.
  2. Shuyun Zhou
    1. Shuyun Zhou is in the Department of Physics, Tsinghua University, Beijing 100084, China, and in the Frontier Science Center for Quantum Information, Tsinghua University, Beijing, China.

Introducing a small twist angle between two graphene layers (2D sheets of carbon atoms) that are stacked on top of each other can drastically change the material’s properties. A striking example of this occurs when a twist angle of about 1.1 degrees is used, producing a material known as magic-angle twisted bilayer graphene (MATBG). MATBG exhibits unusual properties, including unconventional superconductivity1, originating from the formation of ‘flat bands’, in which the electron’s energy is almost independent of its momentum. As a result, the electrons move slowly, interact strongly with each other and behave as if they have a large mass. In a paper in Nature, Xiao et al.2 show that this picture is incomplete: for some momenta, electrons in MATBG are heavy and interact strongly, but for others they are light and mobile.

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Nature 653, 31-32 (2026)

doi: https://doi.org/10.1038/d41586-026-01154-y

References

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Competing Interests

The authors declare no competing interests.

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