The prototypical topological material — the topological insulator — can be in either topological or trivial states. However, there is a richer class of topological materials called Chern insulators, where there are many non-trivial states characterized by a Chern number that can take any integer value. Researchers from the USA and China have now demonstrated a state with a Chern number of two in trilayer graphene with a moiré pattern.
The team showed that at a particular electron density, a plateau appears in the transverse resistivity that is quantized in the same way as the quantum Hall effect with filling fraction equal to two. This indicates that a state has been formed with that Chern number, and its hysteresis in a magnetic field shows that it is ferromagnetic. The manifestation of these states in a material with strong electron interactions opens the possibility that this material can also host non-abelian ‘fractional’ Chern states.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Abergel, D. Chern it up. Nat. Phys. 16, 372 (2020). https://doi.org/10.1038/s41567-020-0881-1
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41567-020-0881-1