[spxtr]

I think CVD graphene (grown, production-scale stuff) has gotten to decent quality these days. There's much more to these devices than graphene, however.

You may have noticed that literally every experimental paper on this stuff has Kenji Watanabe and Takashi Taniguchi as authors. This is because they grow the best hBN crystals in the world and they give them for free to pretty much any researcher who asks nicely. This is amazing and without them the whole field would be way worse off. Their crystals are the bulk sort that needs scotch tape to use, much like graphite needs scotch tape to isolate graphene. I don't think CVD hBN is nearly as good as their stuff yet. The hBN provides an encapsulating dielectric for the graphene, and is critical to getting high-quality devices.

That's just one example of a problem with scaling this stuff, and there are others as well. The field is working to improve these things though, since right now it's super difficult to reproduce any given piece of physics. I think at this point there are exactly 3 ferromagnetic TBG devices in the world, for instance.

[krono]

Any graphene research in particular that you're personally excited about? Past/ongoing/future, theoretical/practical, anything!

The graphene news that I as a non-academic get exposed to, and that is in a form that I can understand (i.e. not highly technical papers), is mostly limited to sensationalist battery improvement articles. A real shame, as so much seems to be going on behind the scenes!

[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.