

Physicists announce graphene’s latest cousin: stanene - rottyguy
http://www.nature.com/news/physicists-announce-graphene-s-latest-cousin-stanene-1.18113

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leni536
They avoid mentioning this being a superconductor because it's not what it is.
However having 0 resistance is a typical property of a superconductor, it's
not the only defining property. I think the established defining properties of
superconductors:

1\. They have 0 resistance.

2\. They have Meissner effect [1].

Being a topological insulator and only conducting along the edges I think (2)
is not possible for this material. It's not like it makes it any less
interesting.

[1]
[https://en.wikipedia.org/wiki/Meissner_effect](https://en.wikipedia.org/wiki/Meissner_effect)

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cynicalkane
Are there any previously known zero-resistance materials without the Meissner
effect?

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dr_zoidberg
I was sure carbon nanotubes matched your description, however the relevant
Wikipedia article[1] mentions the electric properties without refering
explicitly to resistance.

[1]
[https://en.wikipedia.org/wiki/Carbon_nanotube#Electrical_pro...](https://en.wikipedia.org/wiki/Carbon_nanotube#Electrical_properties)

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kordless
Bismuth is some weird shit. My daughter said "it looks like computers" when I
showed her the crystals you can make with it. Faraday was using bismuth coils
to try to unify gravity and was plotting to build anti-gravity devices with
it. It's the most naturally diamagnetic element, meaning you can use it to
make a magnet permanently 'float' in thin air and has one of the lowest values
of thermal conductivity among metals.

It's also what makes Pepto Bismol pink.

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fnordfnordfnord
Got a good source for bismuth?

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kordless
I ordered a pound off Amazon for $24, but the supplier has it cheaper:
RotoMetals.com. I would caution that even though Bismuth is considered non-
toxic, there is some evidence that it will fuck up your brain temporarily. I
strongly suggest heating it outside with ventilation.

~~~
fnordfnordfnord
Thanks!

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steve19
Can someone explain what it means to carry current at room temperature without
any heat loss.

As a layman I interpret this as the material not having any resistance. If it
does have resistance, what is that resistance generating if not heat? What
happens if I put 200 amps through a thin stand of it?

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kazinator
"Loss" is the term we use when we _want_ heat, but it's going away against our
wishes. The correct term for generating and eliminating unwanted heat is
"dissipation".

That this is the intended meaning is clear from the later wording "... being
able to conduct electricity without generating any waste heat".

> _What happens if I put 200 amps through a thin stand of it?_

That's a good question. Even if a material can carry some small current with
apparently zero R, that doesn't mean the same R value applies at a high
current. It could be non-ohmic, that is.

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btashton
If you want to read the details on how it works, I suggest this paper [1]
"Large-gap quantum spin Hall insulators in tin films". The real hope is that
this will be a replacement for the conductors in traditional silicon. You
still have the heat bottleneck when you hit a traditional conductor. The
dissipation free property breaks down at about 100C for this material, so you
are going to have an issue with what ever is interacting with that 200A. [1]
[http://arxiv.org/pdf/1306.3008](http://arxiv.org/pdf/1306.3008)

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ajuc
So, if their predictions are correct - this is a room temperature
superconductor, right?

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ridgeguy
Modeling indicates that a strip of stannene decorated with fluorine atoms at
the edges may be a room temperature superconductor. Here's a link to pretty
modeling pix: [http://www.gizmag.com/stanene-topological-
insulator/29976/](http://www.gizmag.com/stanene-topological-insulator/29976/)

I'll try to add a link to the actual modeling paper later today, sorry but out
of time right now.

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nesu
This would be better if scarcity is not an issue. Carbon is abundant. Tin is
not. It is even more scarce than Lithium.

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stephengillie
So maybe we only use it for long-distance power and communications? I'm
reminded of the Utopia story where, having no need of currency, they used gold
for plumbing, because of its corrosion resistance.

