[spxtr]

I personally think that the Hofstadter butterfly stuff is absolutely gorgeous, and it was a large part of why I started working on 2D materials in the first place.

https://en.wikipedia.org/wiki/Hofstadter%27s_butterfly

In the '70s, Hofstadter wrote about this neat fractal pattern that would show up in the band structure of a material in a sufficiently large magnetic field. Specifically, the magnetic field strength times the crystal unit cell area needed to be big. Magnetic field strength is limited by how much current you can put around a superconducting solenoid. Unit cell area is generally something that you can't change for ordinary crystals: it's just set by the chemistry of the material.

Back in 2012-ish, a few groups managed to artificially increase the area of the unit cell by multiple orders of magnitude by aligning the graphene with hexagonal boron nitride, which has the same crystal structure and a very similar size. When aligned, the moire pattern itself has a large size, and that was enough to see the butterfly.

[krono]

That is indeed very cool and inspirational! I'll be checking out out some of the other concepts that wiki page links to later.

Thanks for sharing, I would have otherwise never come across it.