Electrons flowing like liquid in graphene start a new wave of physics | Hacker News Reader

Electrons flowing like liquid in graphene start a new wave of physics

phys.org

98 pointscarapace16 comments

The study in question, which is much more modest in terms of claims, and much more interesting: http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys...

Key point:

Notably, the measured conductance exceeds the maximum conductance possible for free electrons. This anomalous behaviour is attributed to collective movement of interacting electrons, which ‘shields’ individual carriers from momentum loss at sample boundaries

Wow, could we call graphene a semisuperconductor now?

Rather than meaning “superb conductivity”, superconductivity is a specific electronic state of matter in which the conductivity drops to zero at a certain critical temperature, and magnetic fields are “expelled” from the material. In conventional (low-temperature) superconductors, this is caused by formation of electron pairs (Cooper pairs) that behave as bosons. There is no established mechanism for unconventional (high-temperature) superconductivity.

In any case, the present study does not mean that graphene is a superconductor.

Conductivity drops to zero? Did you mean resistance?

Must be

Correct.

Graphene does not appear to be a superconductor, but apparently the enhanced conductivity is due to electrons forming interesting structures which lower the scattering effects of the atomic lattice. It reminded me about Cooper pairs, hence the joke.

Interesting that increased scattering can increase average current and electron velocity (in a fluidic state) by protecting higher velocity electrons from the edges of the flow. It allows higher conductivity than even theoretically possible in a metal.

I'm usually pessimistic of the hype surrounding graphene, but this is an interesting result. I do hope that there is a bit more room for something like Moore's law.

Some of the biggies were still investing... as of 2014.

http://www.datacenterdynamics.com/content-tracks/servers-sto...

Huh.

Two questions:

1. Any chance this can be replicated in 2D topological insulators?

2. Any chance this could work at room temperature? The paper seems to say <150K.

Tangential question: are the electron "fluid dynamics" of graphene inherently "2D" because it's such a "layered" material and we're talking about such thin slices?

That is, do vortices in the flow behave as if confined to 2 dimensions?

Even if we have to given it a nitrogen bath, it would be incredibly interesting if you could experiment with 2D electron fluid dynamics just by creating graphene structures. (Which I believe can be created via laser circuit printing -- considerably easier than the process for similar things now.)

Yes but bulk graphene has a lot of imperfections changing the electron flow.

This isn't something I know a huge amount about -- could you elaborate?

(I'm mostly just unsure of the scale we're talking about -- what qualifies as "bulk" and what's "a lot"?)

Tangential: are there any commercially-deployed graphene based technologies yet?

https://hobbyking.com/en_us/batteries/turnigy-graphene.html?...

But I feel that it might be a marketing ploy with the product name.

Graphene is used in place of other carbon sources in batteries anodes [1] as well as a variety of inks [2]

[1] https://angstronmaterials.com/product-category/graphene-for-...

[2] https://vorbeck.com/pages/products-conductiveinks

Neat!

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