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What a solid made of electrons looks like (nature.com)
164 points by gmays on Oct 1, 2021 | hide | past | favorite | 69 comments



The phrase "a solid made of electrons" is rather misleading. It's just an ordinary solid (a semiconductor) in which the electrons are made to adopt a particular configuration that does not occur naturally. It is not a "solid" that is only composed of electrons, with no atomic nuclei present.


Even science reporters are having a hard time keeping up with what materials science has been up to lately. With no disrespect to them really intended, they can just about keep up with the semiconductor world's concept of tracking "holes" rather than electrons, but it seems like going any farther into the quasiparticle world is just too much for them. It's rare to see an article that doesn't have some sort of verbiage that indicates the reporter doesn't really understanding what's going on, if indeed I've ever seen one at all.


I get that it's hard.

Often, I'll read a science article in a blog, or local newspaper, or general-interest magazine. I'll see something obviously incorrect, and say "well, it's not a science outlet, they can't be expected to know the science that well, and they're just explaining it to lay people anyway, so it's good enough. I'll double check this with a reliable science news source."

But you'd think if anyone could get it right, and trust their readers to care about them getting it right, it would be Nature! If Nature is going to start going to lower their standards to go after clicks, I dunno what reliable source I'm supposed to double check things with.


> If Nature is going to start going to lower their standards to go after clicks, I dunno what reliable source I'm supposed to double check things with.

Reddit.

I'm serious. If you search for the discussion about the news article on a right subreddit, or HN, or spelunk Twitter enough, there's a good chance you'll find a domain expert - sometimes even the paper's author themselves, or someone who works with them - explaining the science correctly and/or pointing out the bullshit in the press report.

(I wonder if it wouldn't be more efficient if scientists were writing press releases themselves, and the journalists/PR people would be chasing grants for them instead. It seems like a better match for their individual skills anyway.)


>Reddit

>I wonder if it wouldn't be more efficient if scientists were writing press releases themselves

Agree, and I think everyone here has experienced the phenomenon where someone on reddit/HN/twitter has explained something far better than a media outlet. The thing to keep in mind when trying to understand this is that absolutely __everyone__ responds to incentives. With a news organization, no matter what that organization is or their goals, the chief incentive is readership, not accuracy or anything else. Not saying that the writers are anything other than well intentioned and honest or that they don't care deeply about the truth, but the reality of mortal existence is to maximize behaviors that you believe benefit you.

A news org is benefited by people reading what they say, not by being right. Reddit/twitter/HN often is a better source of truth because people often post because they have a desire to be heard, be understood, share information, tell the truth or some other reason that does not involve selling ads against you reading what they say.


> Agree, and I think everyone here has experienced the phenomenon where someone on reddit/HN/twitter has explained something far better than a media outlet.

I've experienced the opposite, though, too.

Posts with thousands upon thousands of upvotes and a little comment with a dozen saying "this is entirely wrong, and here's a bunch of proof, and here's an expert explaining it properly".


That's not really the opposite. That comment with the correction is a part of the submission that's being upvoted.

I do this myself, too: if the discussion underneath a HN submission rescues an otherwise bad article, or even develops into a completely unrelated but interesting tangent, I'll happily upvote it. Sometimes the only value of the submitted article is in the discussion it starts - but that still makes the particular submission valuable.


The correction often receives a minute fraction of the attention the parent post does.


r/Askscience is pretty good though more often than not. It depends a lot on which sub you are in.


I think I've been lied to infinitely more times on Reddit than I have been on PBS.


You have to compare like with like. So try Reddit vs. not just PBS, but literally every TV program you watched and newspaper/magazine you read.


Sounds like messy decentralised authority to most, I guess.

How could that even work?


To borrow from Bojack Horseman:

“See, we can’t be expected to convey complex stuff like this accurately. We’re just not that good at parsing the subtleties of advanced science…”

‘Aren’t y’all the premiere science journal?’


Nature did get it right. The grandparent comment is incorrect. See my other comment.


There's a quote about this that I rather like

> “Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray’s case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the “wet streets cause rain” stories. Paper’s full of them.

> In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.” – Michael Crichton (1942-2008)

Pulled from https://www.epsilontheory.com/gell-mann-amnesia/


In undeserved fairness, I think it's 'just' a clickbait headline, and the author does have a better understanding than you suggest.

The article quickly explains (even the caption on the lead image) that it's an arrangement within a normal solid sheet.

I don't really understand in what sense the internal electron arrangement is 'a solid', but hey, as clickbait, it worked.


I think this is the same argument made by Veritasium - poorly summarized: do whatever it takes to hook people in that have never heard the topic before, then teach them something new. https://youtu.be/S2xHZPH5Sng


But you make it sound like a good thing! I don't like it at all.


Are there any recent summaries by materials scientists written for laypeople?


I really wonder how much is willful ignorance for the benefit of clickbait


A lot of reporters don't get final say on the headlines for their articles. That could be the case here.


The first paragraph of the article clearly describes what the title is actually getting at. It's a perfectly fine title that catches interest.

   If the conditions are just right, some of the electrons inside a material will arrange themselves into a tidy honeycomb pattern — like a solid within a solid. Physicists have now directly imaged these ‘Wigner crystals’, named after the Hungarian-born theorist Eugene Wigner, who first imagined them almost 90 years ago.


It is a solid, and your description isn’t really accurate. It’s not the semiconductor that is being imaged.

The semiconductors are being used to generate a contained cloud of electrons, basically a gas of electrons between the semiconductors.

That gas is then cooled until it crystallizes.

So what you are seeing is a layer of crystallized electrons.

> It is not a "solid" that is only composed of electrons, with no atomic nuclei present.

That is indeed what it is.

https://en.m.wikipedia.org/wiki/Wigner_crystal

From Wikipedia:

“ A Wigner crystal is the solid (crystalline) phase of electrons first predicted by Eugene Wigner in 1934. A gas of electrons moving in 2D or 3D in a uniform, inert, neutralizing background will crystallize and form a lattice if the electron density is less than a critical value.”


Solvated electrons are kind of liquid electrons in that they are a liquid and the anion is just a free electron instead of bound to something.

https://en.wikipedia.org/wiki/Solvated_electron

They can be used to, among other things, reduce pseudoephedrine to methamphetamine.


My first reaction to the headline was "I wonder how many teslas the magnets they're using to keep it together are?"


It’s essentially impossible to make an electron-only substance. The highest density normal-matter stars (white dwarfs) are kept from collapsing with the force of electric repulsion in atoms and they do collapse by proton-electron collision and conversion into neutrons.

From Feynman:

If you were standing at arm’s length from someone and each of you had one percent more electrons than protons, the repelling force would be incredible. How great? Enough to lift the Empire State Building? No! To lift Mount Everest? No! The repulsion would be enough to lift a “weight” equal to that of the entire earth!


> If you were standing at arm's length from someone and each of you had one percent more electrons than protons[[0]]

The latent energy of electromagnetic repulsion between the two of you (never mind between the parts of each of your bodies) would be a bit more than ((1%*80kg/2amu*electroncharge)^2 coulombconst / meter), or on the order of a megaton. Not megaton tnt, a megaton of just energy (comparable to a million tons of antimatter).

0: https://gravityandlevity.wordpress.com/2013/05/22/what-if-i-...


Wow! That is a great visualization of how strong the forces are. It's incredibly strong, I had no idea


So we only need to push a lot of electrons into some matter and get maglev trains without superconductors?


Not really. “only”, no. Trying to levitate trains with static charge would introduce all kinds of hard problems, some easy to imagine, some probably would take a lot of engineering to discover.

The electric field would be hard to contain just under the train, the charge would really really try hard to find somewhere else to be, there would be some crazy ionization of the air going on… flying a kite in a thunderstorm would probably be quite safe by comparison to being close to such an apparatus.


> The phrase "a solid made of electrons" is rather misleading

You've just crushed my dreams of experiencing a Star Trek holodeck or replicator based on this technology.


Thanks for that!

I read the piece, saw the headline and was immediately confused: Like we can have matter that is ELECTRONS only?


Right, that headline had me a bit fazed too. I envisioned a sort of 'crystal' of electrons packed together like people in a tightly packed elevator or oranges in a box.

My mind boggles, if electrons were packed like this then we'd need conditions somewhere between those of a neutron star and a black hole singularity I'd imagine.

Does anyone have any concept of what such matter would look like - its properties, etc.?



Duh, ucks, how did miss that? Thanks for that, I've now corrected it. It's what happens when posting from a phone whilst on the move. Most timely correction too, if I'd reread it tomorrow when too late to correct it then I would really have been fazed! Here's an upvote. :-)


> Does anyone have any concept of what such matter would look like - its properties, etc.?

It would have a lot of charge.


I think the confusion may be the result of a chain of vague associations (or, perhaps, of the "broken telephone effect"): "adopt a particular configuration" -> regular spatial arrangement -> crystal lattice -> crystal-like -> crystal -> solid.



A solid made of electrons would wreak lots of havoc. Probably worse than solid made of antimatter.


so _not_ the strong-interaction material from 3bp? damn


Electron moon looks like the end of the universe

https://what-if.xkcd.com/140/


The title is so clickbaity that it became anti-clickbait (aclickbaity?): I clicked not to learn how this is even possible, but to find out what the eventual catch was.

A better title would be: Here's the first photo ever of a layer of pure electrons. Still click-attracting, yet factually correct (as far as I understand).


I don’t see how that’s not an accurate title. Graphene is a solid and it’s very thin.


Graphene sure is a solid, but it's made out of atoms. However, the thin layer of electrons wedged between the the other parts of the atoms does *not*, to my knowledge, constitute a solid.


All that empty space doe


Mandatory reminder that hexagons are the bestagons.

https://m.youtube.com/watch?v=thOifuHs6eY


How does that generalize to three dimensions?


As a Hexagonal Close Packing lattice, which is the correct way to represent the maximum density arrangement of equal spheres.

If you've seen a stack of spheres, with the bottom layer in rows offset by one radius such that each sphere touches six others at the same height, and the next layer nestled in the intersections of this bottom layer, that's a hexagonal close packing.

Also, the "hexagons are the bestagons" attitude generalizes to three dimensions by dismissing face-centered cubic packing as an inferior way to look at the arrangement.

To generalize the Youtube video aspect, see also this Matt Parker/Steve Mould video on spherical packing: https://www.youtube.com/watch?v=3inLMXcetUA


Given that the stacking of spheres is built from a stack of planar layers, wouldn't that mean that the stack is prone to shearing forces, sliding the layers over each other?

Wouldn't a packing that is irregular in all directions be more robust?

In the "bestagons" video, it is explained that the hexagons win because there are no straight lines in the packing, but I'd expect these to correspond to planes in the 3d case.


There are no continuous planes in the spherical packing layers, either - they all nestle down into gaps in the lower layers.


How does that generalize to four dimensions?


Can anyone explain to me what the implications of this achievement are? What properties does an electron crystal have? And what are its potential applications?


As I understand it there are no known uses.


Link to the original article in Arxiv:

https://arxiv.org/abs/2106.10599


Is their “scanning tunnelling microscope” similar to a atomic force microscope [0]? It also drags a probe over the surface so I’m wondering if they are in the same family.

[0] https://youtu.be/2Kv6KwADn7Q


They're similar. However, an AFM directly measures the deflection of a probe you're rastering, while a STM measures the current caused by quantum tunneling between the probe and the sample. This is extremely sensitive to height because an electron's wavefunction degrades as e^(-sqrt(2*m_e*E)*x/hbar) with distance x and energy barrier E (the measured current will scale with the wavefunction^2). Additionally, a STM allows you to probe electron states as well as just topography.


So this results in a single wavefunction constrained to a particular space group[1]?

[1] https://en.wikipedia.org/wiki/Space_group


I can only imagine the excitement in the room after running the same experiment with the graphene layer on top and seeing this result. I bet it was huge hi-fives!


How is the solidity of ordinary matter not already constituted more or less entirely by electrons and their behavior towards one another?


Scifi concept: solid but low-mass beings with normal electrons but exotic nuclei.


I find materials science fascinating. Is there any recommendation of a blog on this topic for laypeople?


How hard would it be to make a crystal visible to the naked eye?


I imagine a solid made only of electrons would in fact be a bomb, and an absurdly powerful one too. More powerful than a thermonuclear warhead pound for pound, by a big margin.


Unless there's too many of them:

https://en.wikipedia.org/wiki/Degenerate_matter


I saw no photo on mobile or is that just me ?


Visible on mobile, a blue photo. Works in full browser as well as in a WebView.


Just take care not to touch it…


Surely, I can't be the only one who clicked on this thinking it's related to the Electron framework rather than scientific electrons


Blame the awful trend of lazy, ambiguous software naming




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