If you went to the American Physical Society March meeting this year, you probably heard about exciting experiments discovering correlated insulators and superconductivity in twisted bilayer graphene. This is exciting because it seems like the first real observation of strong correlation physics in graphene outside the strong field quantum Hall regime. The moiré patterns generated by twisting these layers are fascinating and is an intriguing “twist” on correlated electron theory as well. You can gauge the fascination of theorists by this by checking out how many papers appeared rapidly on the topic since on the arXiv.
Thanks to my colleague Cenke Xu, who works very quickly, he and I were the first ones in this wave of theories. Our work was very simple, and perhaps naïve in some ways, but it does give an idea of the richness that might occur in these systems. We found that even a relatively simple model leads to topological superconductivity, which would be quite exciting if true. Our paper was recently published in PRL, and you can find a Physics Viewpoint that discusses it as well. I made the image in this post due to a request from the editors for this Viewpoint, but apparently they didn’t like it. So instead I’m sharing it here.
My group is continuing to work on the subject, and I plan to post something on our more recent work soon.