4 ms·

Insulator or superconductor? Physicists find graphene is both

58 points by chmaynard 9y ago

52-6F-62 9y ago
I'm sure I'm getting way ahead of the practical side here, but am I understanding it right that this works at room/atmospheric temperatures? Does this move the needle closer to being able to make the Meissner effect applicable in practical engineering? https://en.wikipedia.org/wiki/Meissner_effect https://en.wikipedia.org/wiki/Meissner_effect
- aidenn0 9y ago
  https://news.ycombinator.com/item?id=16523268 https://news.ycombinator.com/item?id=16523268 links to the Nature abstract showing it's critical temperature is under 2 kelvin, so that's low even for cryogenic superconductors. It's interesting because it's very high temperature given certain properties of the material; if that is confirmed, it may allow greater understanding of superconductivity, which may allow other materials to work at higher temperatures.
  - 52-6F-62 9y ago
    Damn! But any movement is promising. Thanks
- IntronExon 9y ago
  If that’s what floats your boat (sorry) then you might want to look into topological superconductors, which I think might be the way to go. The whole field of topological materials is new enough to hide something surprising and promising.
ben_w 9y ago
Super-transistor. This may have significant implications outside computing, perhaps a switchable Casimir cavity (how do superconductors respond to non-DC currents?) I didn’t see a critical temperature for this in the article, only “100K” for related classes of material. Anyone know the Tc of this?
- emiliobumachar 9y ago
  Super-transistor? I hate to stomp on innovation, but, mechanically rotating parts of a transistor to switch it would seem like a large step backwards relative to the electrically-switchable status quo.
  - skykooler 9y ago
    It's switched by a gate voltage. > The researchers continued to measure the electrical resistance of the material, and found that when they added a certain, small amount of electrons, the electrical current flowed without dissipating energy — just like a superconductor.
- mohaine 9y ago
  > how do superconductors respond to non-DC currents? My understanding is "Poorly". As in not a superconductor for AC for current superconductors.
Armisael16 9y ago
For those who are curious: the Tc is stated as up to 1.7K in the abstract of the Nature preprint (https://www.nature.com/articles/nature26160 https://www.nature.com/articles/nature26160). This isn’t a high-temperature superconductor. It’s still very interesting though (as things in Nature usually are). I’m a little surprised no one had looked at electrical conductivity with misaligned vdW epitaxy - it seems like the an obvious thing to look at to me. They’re still using micro mechanical cleavage (ie, peel it off with tape) - maybe it was a cleanliness or size issue? Maybe it’s just easy hindsight.
rbranson 9y ago
I've been hearing about the magic of Graphene for over a decade now. How close are we to actually getting this stuff into mass-produced goods?
- frozenport 9y ago
  Very long time if at all. Graphene doesn't have an apparent band gap, and this work mention it's still hard to turn it from conducting to non conducting state.
- whoisjuan 9y ago
  Industrial scale production of graphene is still the most challenging area in anything graphene-related. Currently, the are several techniques for large-scale production but nothing large enough that can fit the supply chain of mass-produced goods like batteries.
- godelski 9y ago
  The hard thing is making large sheets and single layer. Multi-layer and small sheets is pretty easy. Too many sheets, and you have graphite though. But those small chunks have some useful properties (same with CNTs, which you can make with a detonation). Also, realize that they don't have 0 resistance (which is a superconductor), read as "it creates heat". This limits the amount of current that you can drive through it. So there's still a lot of problems that need to be solved. But there are definitely huge interests in also looking at using it for filtering molecules. But this is also difficult to do with precision. And that's the root of the problem, precision and consistency. I know that doesn't exactly answer your question, but all I can say is that it feels like we are close.
- Maybestring 9y ago
  https://www.head.com/us-US/sports/tennis/technology/graphene-xt/ https://www.head.com/us-US/sports/tennis/technology/graphene... Not to say that it's doing much good here...
- tlack 9y ago
  Good question. I'm eager too. I've been able to buy Graphene Concrete Admixture and graphene-infused PLA filament for my 3D printer though.
olympus 9y ago
Oh, look. Another great thing that graphene can do. I'm starting to think that I'll see genetically engineered pro athletes before I get to see graphene powered gadgets. And probably I'll see true human level AI before mass market graphene as well.
- lern_too_spel 9y ago
  You have already seen genetically engineered pro athletes. https://www.smh.com.au/news/basketball/yao-ming-the-basketball-giant-made-in-china-by-order-of-the-state/2006/01/18/1137553645228.html https://www.smh.com.au/news/basketball/yao-ming-the-basketba...
  - Phrodo_00 9y ago
    > The two were encouraged to marry in a system with undertones of eugenics, the controversial gene-pool manipulation espoused by the Nazis and previously trumpeted by Beijing. Strangely, no mention of US' being really into it before WWII
    - Retra 9y ago
      Why is it strange?
  - grzm 9y ago
    The article you provided mentions that his parents were encouraged to marry. > The two were encouraged to marry in a system with undertones of eugenics, the controversial gene-pool manipulation espoused by the Nazis and previously trumpeted by Beijing. > It wasn't a national breeding program, it was a desire among Shanghai officials for them to get together," Larmer said. "But when Yao was born, everybody in the sports community in Shanghai and nationally knew he was something special." While I agree that's unsavory, that's not what most would consider "genetically engineered."
    - olympus 9y ago
      Yeah, I meant something along the lines of using CRISPR or a future derivative to make a person genetically predisposed to having the fastest mind, most durable body, and best hand-eye coordination.

58 points by chmaynard 9y ago

I'm sure I'm getting way ahead of the practical side here, but am I understanding it right that this works at room/atmospheric temperatures? Does this move the needle closer to being able to make the Meissner effect applicable in practical engineering? https://en.wikipedia.org/wiki/Meissner_effect https://en.wikipedia.org/wiki/Meissner_effect

aidenn0 9y ago
https://news.ycombinator.com/item?id=16523268 https://news.ycombinator.com/item?id=16523268 links to the Nature abstract showing it's critical temperature is under 2 kelvin, so that's low even for cryogenic superconductors. It's interesting because it's very high temperature given certain properties of the material; if that is confirmed, it may allow greater understanding of superconductivity, which may allow other materials to work at higher temperatures.
- 52-6F-62 9y ago
  Damn! But any movement is promising. Thanks
IntronExon 9y ago
If that’s what floats your boat (sorry) then you might want to look into topological superconductors, which I think might be the way to go. The whole field of topological materials is new enough to hide something surprising and promising.

ben_w 9y ago

Super-transistor. This may have significant implications outside computing, perhaps a switchable Casimir cavity (how do superconductors respond to non-DC currents?) I didn’t see a critical temperature for this in the article, only “100K” for related classes of material. Anyone know the Tc of this?

emiliobumachar 9y ago
Super-transistor? I hate to stomp on innovation, but, mechanically rotating parts of a transistor to switch it would seem like a large step backwards relative to the electrically-switchable status quo.
- skykooler 9y ago
  It's switched by a gate voltage. > The researchers continued to measure the electrical resistance of the material, and found that when they added a certain, small amount of electrons, the electrical current flowed without dissipating energy — just like a superconductor.
mohaine 9y ago
> how do superconductors respond to non-DC currents? My understanding is "Poorly". As in not a superconductor for AC for current superconductors.

Armisael16 9y ago

For those who are curious: the Tc is stated as up to 1.7K in the abstract of the Nature preprint (https://www.nature.com/articles/nature26160 https://www.nature.com/articles/nature26160). This isn’t a high-temperature superconductor. It’s still very interesting though (as things in Nature usually are). I’m a little surprised no one had looked at electrical conductivity with misaligned vdW epitaxy - it seems like the an obvious thing to look at to me. They’re still using micro mechanical cleavage (ie, peel it off with tape) - maybe it was a cleanliness or size issue? Maybe it’s just easy hindsight.

rbranson 9y ago

I've been hearing about the magic of Graphene for over a decade now. How close are we to actually getting this stuff into mass-produced goods?

frozenport 9y ago
Very long time if at all. Graphene doesn't have an apparent band gap, and this work mention it's still hard to turn it from conducting to non conducting state.
whoisjuan 9y ago
Industrial scale production of graphene is still the most challenging area in anything graphene-related. Currently, the are several techniques for large-scale production but nothing large enough that can fit the supply chain of mass-produced goods like batteries.
godelski 9y ago
The hard thing is making large sheets and single layer. Multi-layer and small sheets is pretty easy. Too many sheets, and you have graphite though. But those small chunks have some useful properties (same with CNTs, which you can make with a detonation). Also, realize that they don't have 0 resistance (which is a superconductor), read as "it creates heat". This limits the amount of current that you can drive through it. So there's still a lot of problems that need to be solved. But there are definitely huge interests in also looking at using it for filtering molecules. But this is also difficult to do with precision. And that's the root of the problem, precision and consistency. I know that doesn't exactly answer your question, but all I can say is that it feels like we are close.
Maybestring 9y ago
https://www.head.com/us-US/sports/tennis/technology/graphene-xt/ https://www.head.com/us-US/sports/tennis/technology/graphene... Not to say that it's doing much good here...
tlack 9y ago
Good question. I'm eager too. I've been able to buy Graphene Concrete Admixture and graphene-infused PLA filament for my 3D printer though.

olympus 9y ago

Oh, look. Another great thing that graphene can do. I'm starting to think that I'll see genetically engineered pro athletes before I get to see graphene powered gadgets. And probably I'll see true human level AI before mass market graphene as well.

lern_too_spel 9y ago
You have already seen genetically engineered pro athletes. https://www.smh.com.au/news/basketball/yao-ming-the-basketball-giant-made-in-china-by-order-of-the-state/2006/01/18/1137553645228.html https://www.smh.com.au/news/basketball/yao-ming-the-basketba...
- Phrodo_00 9y ago
  > The two were encouraged to marry in a system with undertones of eugenics, the controversial gene-pool manipulation espoused by the Nazis and previously trumpeted by Beijing. Strangely, no mention of US' being really into it before WWII
  - Retra 9y ago
    Why is it strange?
- grzm 9y ago
  The article you provided mentions that his parents were encouraged to marry. > The two were encouraged to marry in a system with undertones of eugenics, the controversial gene-pool manipulation espoused by the Nazis and previously trumpeted by Beijing. > It wasn't a national breeding program, it was a desire among Shanghai officials for them to get together," Larmer said. "But when Yao was born, everybody in the sports community in Shanghai and nationally knew he was something special." While I agree that's unsavory, that's not what most would consider "genetically engineered."
  - olympus 9y ago
    Yeah, I meant something along the lines of using CRISPR or a future derivative to make a person genetically predisposed to having the fastest mind, most durable body, and best hand-eye coordination.