Silicon Superconductors

Diana writes "Physicists at CNRS have demonstrated superconductivity in silicon, the element long known for its semiconducting properties. High doping is the key — by substituting 9% of the silicon atoms with boron atoms, it was found that the resistance of the material drops sharply when cooled below 0.35 K. A small increase in the transition temperature is likely with further work."

OK, science is cool and everything

[multiplexo (27356)]

But you can make pretty much anything superconductive if you get it down below .5 Kelvin. I mean really, go much lower and you can make Twinkies superconductive much less boron doped silicon.

Re:OK, science is cool and everything

[RuBLed (995686)]

You forgot to put the link... http://www.twinkiesproject.com/ [twinkiesproject.com]

Re:

[Walt Dismal (534799)]

I, for one, welcome our new superconductive Twinkie overlords.

So.....

[PHAEDRU5 (213667)]

Superconductivity in non-superconductive materials, except where they've been doped to be superconductive.

Makes me want to get back to the pub.

Re:

[El Cubano (631386)]

by substituting 9% of the silicon atoms with boron atoms

That makes me wonder if it is still legitimately considered silicon. I mean, replacing nearly 10% of it with another element must mean that it falls into another classification. I don't think it could be considered a compound since the atoms are not bonding in the traditional sense, they are simply occupying places in a crystalline structure. Perhaps it is more appropriate to call it a "silicon-based material"

Re:So.....

[Dunbal (464142)]

replacing nearly 10% of it with another element must mean that it falls into another classification.

      An alloy, if you will?

Re:

[gt_mattex (1016103)]

Superconductivity in non-superconductive materials, except where they've been doped to be superconductive.

Makes me want to get back to the pub.

After your good and 'doped' up do we throw you in the freezer and run a current through you?

Oh, you are naughty...

[PHAEDRU5 (213667)]

...but I like you...

How useful is this?

[TubeSteak (669689)]

0.35 K? as in... barely above absolute zero?

Etienne says that they will probably be able to increase the transition temperature a bit further, although the material will be unlikely to have any applications in consumer devices.

What non-consumer applications will it have? Getting something down to .35K isn't exactly trivial...

IIRC, anything that doesn't superconduct at the temp of liquid nitrogen is a pain in the ass to use.

Re:How useful is this?

[swordgeek (112599)]

First of all, it's called RESEARCH! It's a very new and different bit of science--who knows where it could lead us?

Secondly, just because things are a pain in the ass doesn't mean they don't have useful applications. NMR/MRI have been dependent on low-temp superconductors (i.e. liquid He or even colder) for decades, and they're immensely important for research and medicine.

Re:How useful is this?

[Fred_A (10934)]

What non-consumer applications will it have? Getting something down to .35K isn't exactly trivial...

Agreed, I know I definitely am going to need bigger fans to get to that level of cooling in my machine. Much bigger fans.

superconducting semiconductor?

[HAL9000_mirror (1029222)]

whatever that means!

Re:superconducting semiconductor?

[NanoProf (245372)]

It means quite a bit. Strontium titanate was the first superconducting semiconductor, predicted to be so by Marvin Cohen (my theses advisor :-) and later confirmed by experiment. The general idea is that a semiconductor with multiple valleys in the conduction band into which to place dopant electrons can rapidly develop low-energy electronic states under doping, and these are the states that couple to lattice vibrations and so generate superconductivity. If you don't have a problem with the term "doped semiconductor," (which is a material that actually conducts- how do you think those electrons get through transistors on computer chips :-), then you should be ok with "superconducting semiconductor".

Re:

[feranick (858651)]

Silicon is a semiconductor (at room temperature, undoped). If doped and at 0.35K, it becomes superconductive. Saying "superconductive semiconductor" is quite misleading, like saying, "liquid ice". It's the same material, but it has different properties at different Temperatures.

Be Sure To Practice Safe Si

[ryanisflyboy (202507)]

And just to make the article more clear: Let's substitute "boron" with Tom (hey, what guy wouldn't want more boron?), and "silicon" with Suzie (hey, what girl woudln't want more, eh, yeah.).

"Because it has one fewer electron than Suzie available for bonding with neighbouring atoms, Tom incorporated into Suzie leaves a positively-charged "hole" at each site where Tom's "missing" electron would be paired with one of Suzie's."

Well they did do it in France, you know.

Missing the point...

[physicsphairy (720718)]

If we can turn semiconductors into superconductors, then we can probably turn my band conductor into a semi-conductor, which would at the very least mean less thrown chairs during parent teacher conferences, and less thrown chairs can only be good for Linux!

(Yes, that happened; and yes, he is still in band director.)

Re:

[Duhavid (677874)]

Yes...

Windows, windows uber alles...

A popular favorite in his class.

Boron

[sankyuu (847178)]

Gah!

How is this useful? What are applications? Blahblah

Since when did science have to have applications?
(This isn't sarcasm; science is about discovery. Applications of those discoveries are mostly accident. You can't automatically "succeed" at science. Failing to find a room-temperature superconductor isn't failing per se; it means succeeding to eliminate another coulda been material. Finding dead ends is part of the quest. And this result might not yet be a dead end.)

So far, most of the comments have been posted by boring morons.

-A bored moron

Re:

[espressojim (224775)]

Eh, just because you haven't found a material that is a superconductor at room temperature doesn't mean that there aren't any. It's easy to say "X can happen, because we have example Y", but you can't say "X can't happen, because we have example Y". All you can do is state all the places you've seen that it doesn't work. Sometimes, you can generalize those results (water from the atlantic ocean is not made of cheese, and thus we have no reason to believe that water from the pacific is either.)

Negative re

Too Much Battlestar Galactica.

[camperdave (969942)]

I've been watching too much of the original Battlestar Galactica. With their "centons", "sectons", "furlons", "crawlons", and of course "Cylons", when I saw the term boron, my first thought was that it was some sort of unit of boredom. Then I read the article, and realized I was right.

they got it all backwards

[LM741N (258038)]

Boron was made superconducting by doping it with 90% silicon.

Re:

[TheSync (5291)]

Boron has already been made superconducting [physicsweb.org] five years ago. It becomes superconducting when squeezed with a pressure of 160 gigapascals at a transition temperature of 6K.

0.35K is rather cold

[NixieBunny (859050)]

I realize that this is just a laboratory curiosity at this point, and no one would try to use such a compound commercially. Still, a brief description of what it's like to make 0.35K is in order.

I work on a radiotelescope that uses receivers cooled to 4K. These use a helium refrigerator that works just like the Freon thing in your car but using helium instead of Freon as the phase-change medium. It takes three stages of cooling (with compressors and heat exchangers) to get to the 4K point. It also takes 10 kW of electrical power to cool one watt of load to 4K.

We until recently had one receiver, a bolometer, that was cooled to 0.4K using the 3He isotope of helium that has a lower boiling point. The refrigerator for this is a fist-sized gadget that uses a charcoal trap, a heater resistor and some plumbing to make a refrigerator that can be cycled to produce 0.4K for a day or so at a time. It makes many microwatts of 0.4K coldness from less than one watt of 4K coldness.

Unfortunately, the 3He leaked out and the gizmo is currently a paperweight since it was made by a very clever French guy who's no longer in the business.

You can still buy 3He refrigerators from other manufacturers, but they are two feet long. The 3He is available for several thousand dollars a bottle.

Re:0.35K is rather cold

[wass (72082)]

Getting to 4K is relatively easy, you get a dewar of helium (this is the relatively abundant He4 isotope) at roughly $4 per liter. You can cool to 1K relatively easily too by pumping on the vapor over the helium, evaporatively cooling ot down to 1K. It's inefficient to do this, though, people tend to build a 1K pot into their cryostat to only pump on a small volume of helium to cool their system to 1K, not the whole dewar.

Regarding the Helium 3 Fridge, that's actually doing the EXACT same thing as the 1K pot above, you're evaporatively pumping He3 with the charcoal sorb. Since He3 is rare and expensive, this is done in a closed system and recycled.

I know your pain, though, our He3 fridge has a leak, luckily not on the He3 system (He3 is super expensive), and it's been a pain in the ass to try to fix. To fix your system, you probably don't need that French dude to fix it, get a leak checker (find some experimental condensed matter guys that do vacuum sputtering or evaporation work, they'll have a leak checker), track down the leak on your He3 system, plug the leak (silver solder if possible w/ your machine shop), then pay some $$$ to inject some He3 back in when you're damn sure you've got no more leaks left.

This will be useful in low temperature physics

[ebers (816511)]

Yes, 0.35 K is really cold. Refridgeration methods that reach this temperature cost ~ $100,000 and use the helium-3 isotope as the working fluid, which costs several hundred dollars per gaseous liter at STP. But this may still be useful because there is lots of established technology for making very small things out of silicon, and lots of fundemental physics that can only be done at very small length scales and in very cold environments.

Re:

[joto (134244)]

Thank you. You are the first to give a plausible explanation as to why anyone would be interested in another superconductor, when it needs such a low temperature. However, if people are interested in doing low-temperature nanoscale physics experiments, I'm all for that!

start the car

[ElephanTS (624421)]

I tried super-doping myself but it got boron after a while.

Pamela Anderson

[corychristison (951993)]

So I guess Pamela Anderson is more useful than we thought! Other than the obvious, of course. ;-)

Things

[mqduck (232646)]

I can do things I normally can't when I'm doped, too.

Re:So who the fuck cares

[HAL9000_mirror (1029222)]

One should not always relate things to 'applied' science. There is a predecessor called 'pure' science that acts as an enabler for rest of the world. Sure average Joe doesn't care but it is a significant improvement in the scientific world. Now many critical research can be performed on "silicon" (although at insanely low temperature). Remember the time when there were only few elements in the world that exhibited the property of superconducting? Now Silicon is yet another addition and considering how Silicon is closely related to computing, this could be a jump board for the speed-demanding future ahead.

Re:So who the fuck cares

[dbIII (701233)]

Who cares? People who are trying to work out how superconductivity happens so that there may been room temperature superconductivity some day - that is who cares. Please keep the profanity to yourself as you play in the garden and let the Moorlocks get back to it.

Re:

[djupedal (584558)]

Please keep the profanity to yourself

Now there's something not seen every day - a wannabe list-mom, not afraid to strike out. Wickedly delivered, sure to strike fear in the heart of the evil-doer you've so publically chastised. Can we have another?

Let me offer just a small bit of advice, and remember, it is promised to be worth exactly what you paid for it.

Stop - don't do that again. You'll only bring attention to yourself as being a target ripe for kicking, while setting yourself up for a tight-fitting suit of frustration. Most forums h

Re:

[theshowmecanuck (703852)]

If you simply can't resist the urge to police another human being, try hanging out near the Slushy machine at your favorite 7-11.... Put it on your resume, perhaps. Who knows, with the way things are going, the need for easily identifiable assholes such as yourself...

Ahhh, yah. What you said.

Re:

[dbIII (701233)]

So - are those couple of sentences as pathetic as the person who replies to it with a couple of paragraphs? OK so some of it was funny.

I'm pointing out that in my opinion an ill informed idiot is also a pointlessly swearing idiot. A worthless argument suddenly carries weight and gets attention becuase it makes it look like strong feelings are involved - it looked to me like pointless swearing to get attention to a stupid argument. For some reason this made me think of marketing people creeping into slash

Re:

[shaitand (626655)]

"pointlessly swearing idiot"

I am going to ignore the name-calling you wielded in that same statement. Who says there has to be a point to swearing? In fact, last I checked this is supposed to be a new millennium staffed with new and improved intelligent human beings. An intelligent human will immediately dismiss the entire concept of 'swear' words, 'bad' words, and 'profanity' as illogical nonsense. Words can no more be profane or bad than guns can kill people. Words, Guns, Knives, Hammers, Racks, Hack Saws

Re:So who the fuck cares

[Heir Of The Mess (939658)]

It's just a process of discovery to advance science. If we didn't go through these scientific processes of discovery then we would still have people running around thinking that everything was controlled by some big booming voice in the sky. Oh wait...

Re:

[Alsee (515537)]

people running around thinking that everything was controlled by some big booming voice in the sky

They are called radio waves. Rush Limbaugh's voice isn't really coming from the sky.

-

Re:So who the fuck cares

[swordgeek (112599)]

The only thing worse than an aggressively ignorant idiot is a foul-mouthed one.

In the 1830s, it was discovered that some materials acted as neither pure conductors nor pure insulators. They called them semiconductors, and they were a curiosity until the 1890s, when they were found to be useful as rectifiers and photovoltaic cells. Another 40 years later, and people started to consider them as a replacement for the triode vacuum tube, which was immensely useful but fragile and difficult to deal with.

Pure research in new directions isn't just allowed because it 'might lead to something,' it's absolutely essential in order to progress beyond refinement of the existing.

Re:

[feranick (858651)]

You don't seem familiar with solid state physics. A 'pure conductor" is defined very well as a material where electrons are present in the conduction band, and weekly bounded to the core. A pure insulator has the conduction band empty. and a big band gap prevents electron from the valence band (closer to the core) to make the jump into the conduction band. Semiconductors are somewhere in between, they have a small gap so electron can effectively make the jump into the conduction band under specific conditio

Re:

[dbIII (701233)]

You don't seem familiar with solid state physics ... "A 'pure conductor" is defined very well ... Semiconductors ... pure insulator ... Before you talk, shut up" (and think).

Nasty.

Now if I take a BiSiCuYt superconductor at a low temperature it superconducts, higher and it semiconducts, room temperature and it insulates. Why is this so? Has the mechanism behind superconductivity been worked out in the last couple of years when I wasn't paying attention - and can you explain it?

Mod the parent down

[feranick (858651)]

Please! Since when everything is supposed to make sense only if it has tech applications? You seem to be missing the point of science really. The fact that doped silicon exhibit superconductivity is per se a great discovery. There are plenty of examples of "useless" science: black holes, dark matter, superfluidity. You may not care (busy playing your new PS3?). The rest of us really do.

Re:

[Ididerus (898803)]

Um, lots of people care. The MRI machines use super-conducting material cooled with liquid nitrogen, this might make them more efficient. Plus, when I've got my Mag-Lev skate board, you're gonna think I'm pretty cool too. Even if I
am in space.

BTW, 0.35 K = -272 C

Space is around 2.7K or, -270 C (Assuming no Extraneous Radiation)

Re:

[windsurfer619 (958212)]

But you must admit, getting an object to 0.35 K from 3 K is a lot easier than bringing it from 300 K.

Re:So who the fuck cares

[Sparr0 (451780)]

Not really. No one makes a 300K->.35K cooling device. Put simply, you take a 3K->.35K refrigerator and set it inside a 300K->3K refrigerator. Since any lab or plant that is doing this sort of work already has the 300K->3K unit, using said unit is a trivial addition to the process of using the new "low temp" unit.

Re:

[Tyler Eaves (344284)]

That's a common misconception. Space has no temperature. It is neither cold nor hot. You must have a molecular medium to have a temperature. It's kinda analogues to the water pressure in an empty glass.

Re:

[shaitand (626655)]

So you are saying that all that is needed to attain absolute zero is a vacuum?

Re:So who the fuck cares

[agentcdog (885108)]

No. You are wrong. Read up about blackbody radiation. Space is like a big cavity with blackbody radiation that's about 3k. That's the thing about electromagnetic radiation - you don't need a medium. Let me make it clear... If you brought a piece of metal into space, would it keep cooling off by radiation? No. Why? Because at 3 kelvin space would be giving it as much energy as it is shedding. The pipe and space would be at an equilibrium state when the pipe reached 3 kelvin. You see how this is real temperature? Good.

Re:

[Feyr (449684)]

Damn right. don't come here, you'll freeze and your fingers and other protruding parts will fall off.

that also mean we get to keep all the cute chix0rs

Re:Um

[wass (72082)]

Pretty much anything will superconduct below 0.35K. How is this news?

Actually, no, many things do not superconduct at arbitrarily low temperature, common examples being some of the best room-temperatures conductors we know of (eg copper and gold). Pure silicon also does not superconduct, as explained in TFA, which was known for some time.

As for this being news, well it interests me because I do experimental research with superconductors. But I'm surprised it made the front page of slashdot.

Re:

[mikael (484)]

Wikipedia [wikipedia.org] has an explanation.

The electrical resistivity of a metallic conductor decreases gradually as the temperature is lowered. However, in ordinary conductors such as copper and silver, impurities and other defects impose a lower limit. Even near absolute zero a real sample of copper shows a non-zero resistance.