
A predicted superconductor might work at a record-breaking 200° Celsius - respinal
https://www.sciencenews.org/article/predicted-superconductor-record-breaking-temperature-200-celsius
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qcj
Since this is the second story about this kind of research that has been
posted this week, I feel it should be made clear that the purpose of this kind
of experiment is not to develop room temperature superconductors for use in
devices, but to study the physics of BCS (normal, "low temperature"
superconductivity seen in metals like mercury, as opposed to that seen in
materials like YBCO) superconductivity in materials with much lighter nuclei,
and to get an idea of what might occur in theoretical states of matter like
metallic hydrogen. It is only "applied" in the sense that it allows one to
understand the mechanisms behind superconductivity, no one doing this research
thinks that this will be a useful mechanism for making superconducting
transmission lines or whatever.

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outside1234
"It must be squeezed to extremely high pressure, nearly 2.5 million times the
pressure of Earth’s atmosphere"

I think I'd rather have the low Kelvin superconductor, thanks.

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SketchySeaBeast
Yeah, this seems like it might possibly be not worth the effort. I'm curious
as to applications for this - that's a pressure and temperature that's not
practical either.

I mean, unless intel is really committed to it's 14 nm node.

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chr1
A group of these superconductors was discovered by a computer simulation [1],
they are not meant to be used in technology, but better understanding of
mechanism by which superconductors work, and improvements in quantum
mechanical simulations may help in the future to create materials where some
atoms are squeezed together by the interaction with other atoms in the
material instead of external pressure.

[1] [https://uspex-team.org/en](https://uspex-team.org/en)

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davidhyde
I wonder if the cross section area of the superconductor is relevant. If it is
not then it could conceivably be enclosed inside a carbon nanotube to hold its
pressure. A carbon nanotube can hold about 620,000 atmospheres of pressure.
Not quite 2.5 million but maybe another substance can be found that can
superconduct at a lower pressure. Perhaps multi-walled tubes could be made.
I'm sure someone has already thought about this though.

[https://en.wikipedia.org/wiki/Carbon_nanotube#Mechanical](https://en.wikipedia.org/wiki/Carbon_nanotube#Mechanical)

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Geee
It doesn't even have to be nanotube? Just regular diamond tube or something
else that can hold the pressure. Maybe it could be done in the same way
diamonds are made, just put the superconducting stuff inside first.

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dagw
The pressures we're talking about here are almost 2 orders of magnitude more
than what is used to make diamonds.

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Geee
They use diamond anvils to create the required pressures though. I wonder if
it's somehow possible to lock these kind of molecules or other stuff inside an
unbroken diamond carbon lattice and what would happen.

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molyss
Can we please change the meaning of “high temp superconductors” to “material
that start being super conductors and high temperature and low pressures” ?
Everyone agrees that these records don’t mean anything in term of direct
applications. I agree that they give us a way to check our theoretical models,
which might help getting to usable stuff, but all the “record shattering”
language is really not making science look very smart IMO.

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qcj
I think this argument is quite facile. These people are scientists trying to
understand superconductivity at a basic level, and this theoretical research
(as well as the experimental results posted on this forum earlier this week)
are a genuine advancement in that field. You are judging this research based
on how it is directly applicable to making handheld devices with room
temperature superconductors when that is not what these people are attempting
to do at all. The fact that a superconducting state can be maintained at these
temperatures at all is, indeed, "record shattering". We do not have the
ability to simply engineer a material that can superconduct at ambient
temperature and pressure at will. I don't mean to be to confrontational, but
reading the comments on these articles it really pisses me off to see the hard
work of actual scientists judged by the rubric of whatever science fiction
garbage internet commenters think should be possible.

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asdfman123
Yeah, it sounds like the only downside to calling them "high temperature
superconductors" is it briefly misleads you when skimming HN headlines.

I don't think scientists should change their entire domain-specific language
to improve your web browsing experience.

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molyss
And that attitude is in my opinion what will increasingly get in the way of
science being disregarded

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Tade0
To me the most important thing here is that we can finally make an educated
guess regarding the circumstances in which something becomes a superconductor.

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berbec
While this seems... interesting... Isn't it actually safer and easier to cool
something to 2°K than to pressurize to 36,000,000 psi

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brohee
The huge pressure would only be needed during manufacturing no?

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itcrowd
The linked article is a bit ambiguous about it, I think, but the abstract [1]
is clear: the pressure must be applied for the material to be superconducting:

> Here, we identify an alternative clathrate structure in ternary Li2MgH16
> with a remarkably high estimated Tc of ∼473 K at 250 GPa [...]

[1]
[https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12...](https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.097001)

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ableal
_" The newly predicted superconductor — a compound of hydrogen, magnesium and
lithium — [...] must be squeezed to extremely high pressure, nearly 2.5
million times the pressure of Earth’s atmosphere [...]"_

Sounds risky ...

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jarfil
It doesn't seem to be a gas, so applying pressure would be as easy as
tightening the enclosure, like fastening a bolt. Cables could be made by just
sticking a superconducting core inside a compression sleeve, although they'd
probably have to be segmented, and breaking the sleeve in any place could make
the core stop superconducting and overheat pretty fast. Other than that, it
should be perfectly safe.

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lvh
The values suggested are north of the ultimate tensile strength for carbon
nanotubes and graphene. It’s in the ballpark of the center of the earth. I
don’t think it’s as simple as tightening a bolt.

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molyss
I think it’s literally tightening a few bolts :
[https://en.m.wikipedia.org/wiki/Diamond_anvil_cell](https://en.m.wikipedia.org/wiki/Diamond_anvil_cell)

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lvh
A DAC works because you use it on a tiny surface area (measured in microns).
The application was power transmission cables.

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_Microft
_At high pressures_.

Seriously, I think I need to start a Twitter account for that ;)

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benj111
I don't really have a good understanding for why the high pressures are
required.

Any ELI 5 explanations?

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klyrs
I'm not a physicist, but I work adjacent to people who do neat stuff with
superconductors... hopefully they wouldn't be too mad about the broad strokes
I'm using here.

Superconductivity isn't just a property of a material -- it's a property of an
arrangement of atoms. When you put a material under extreme pressures, the
atoms are smashed closer together; and the properties of the material can
change significantly. For example, diamonds are made by smashing graphite at
extreme pressures -- sufficiently high pressure can completely rearrange the
crystalline structure.

That prepares us for the question; what's superconductivity? The answer is
complicated, physicists don't really know the full story; but here's a
simplified intuitive picture. We imagine atoms as being positively-charged
nuclei with clouds of negatively-charged electrons. When these atoms are
packed into a crystalline lattice, and the resulting material is a conductor,
then the electrons are fairly free to move about the whole lattice -- they
aren't bound to a single atom. When the electrons move about, they attract
nearby nuclei -- the atoms in the lattice shift towards them! In a
superconductor, something quite amazing happens: when atoms shift towards one
electron, it can make room for another electron -- this process causes the
electrons to buddy up, and act in a coordinated fashion. These two electrons
quickly make other friends, and in short order they're all acting in concert!

So, back to high-pressure superconductivity. We've applied a high amount of
pressure to a material which isn't normally superconducting. Its atoms have
rearranged themselves into a new crystalline lattice, which is quite densely
packed. The electrons, too, must be densely packed -- so they have greater
opportunities to make friends.

