Surprise graphene discovery could unlock secrets of superconductivity | Hacker News Reader

Surprise graphene discovery could unlock secrets of superconductivity

nature.com

71 pointsrbanffy13 comments

Previous discussion: https://news.ycombinator.com/item?id=17743796

Superconductors come broadly in two types: conventional, in which the activity can be explained by the mainstream theory of superconductivity, and unconventional, where it can’t. The latest studies suggest that graphene’s superconducting behaviour is unconventional — and has parallels with activity seen in other unconventional superconductors called cuprates. These complex copper oxides have been known to conduct electricity at up to 133 degrees above absolute zero. And although physicists have focused on cuprates for three decades in their search for room-temperature superconductors, the underlying mechanism has baffled them.

Magic angle graphene (sheets twisted 1.1 degree relative to each other) isn't a temperature breakthrough because the sample must be cooled to 1.7 K.

Rather, it appears to be a novel system for studying unconventional superconductors. The best-studied example to date is based on cuprates. Both cuprates and magic angle graphene are characterized by insulting state very close to a superconductivity state.

The hope seems to be that magic angle graphene will prove to be a better system for understanding unconventional superconductivity. That could lead to high temperature superconductors.

In contrast to cuprates, the stacked graphene system is relatively simple and the material is well-understood. “The stunning implication is that cuprate superconductivity was something simple all along. It was just hard to calculate properly,” says Laughlin.

I'm going to take a wild guess that it has something to do with electron de broglie wavelength somehow being resonant in certain lattice structures. Twists in graphene layers are known to create a morie pattern giving it a quasi-periodic structure at much higher length scales than simple atomic lattices. This is likely related.

>And although the system still needed to be cooled to 1.7 degrees above absolute zero,

awww :(

Yeah, in the beginning of the article they talk about room temperature super conductors, and than this...

Yeah, that was a whole lot of lead up for that result.

“It’s so much worse than known high temperature superconductors!”

Correct me if I'm wrong, but I think the significance of this finding is not so much about temperature, rather it's a big piece of the puzzle in understanding superconductivity. This is the first time that we are able to achieve superconductivity via mechanical property rather than molecular property. Our current superconductors are based some crazy alloys, and we have little insight of why they are superconductive.

In this finding they were able to make graphene superconductive by simply shifting two sheets of graphene by 1.1 degree angle. Graphene consists of only carbon atoms, its atomic properties are much easier to model than an alloy, so by examining why this magical angle work, it can greatly help us understand why superconductivity occur, eventually helping us design higher temperature superconductors.

Correct. It's a significant finding. I'm annoyed at the breathless explanations of our current superconductor situation as a lead in followed by this revelation that this new superconductor isn't really useful as a high-temperature superconductor at all.

I.e. I'm annoyed by the writing not unimpressed with the science :-)

Any article with the words "graphene breakthrough/discovery" or "battery breakthrough/discovery" should get a blanket ban...

I guess...

It's interesting that every single article about graphene shows a 3D model of a plane of molecules, but never a photo...

Science headlines with the word 'could', 'could' hold the secret of eternal youth.

> Graphene can do just about anything except leave the lab.

This is six months old

Reply on news.ycombinator.com