First Superconducting Transistor Created 124
holy_calamity writes "New Scientist reports that the first working superconducting transistor has been created, by researchers at the University of Geneva. Field effect transistors with zero electrical resistance would allow much faster operations. Only drawback is they need to be supercooled, something that may be addressed by improving the materials used."
Gift for understatement (Score:5, Informative)
"Only drawback is they need to be supercooled, something that may be addressed by improving the materials used." - that last part is a bit of an understatement. We're still decades (centuries?) away from room temperature superconductors [slashdot.org].
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We're still decades (centuries?) [sic] away from room temperature superconductors.
Why would that be? After all, cold-fusion [std.com] is already a reality!
=Smidge=
Re:Gift for understatement (Score:5, Insightful)
Sure, but you don't have to do it at room temperature, either. There are superconductors at Liquid Nitrogen temps. Certainly most MRI machines use Liquid Helium temperature superconductors. They, of course, cost millions of dollars, but they are still used quite frequently.
IIRC, LN costs about the same as milk (~$3/gallon). If the rate of evaporation wasn't too great, it would just be an on-going charge. Say it was 1 gallon/month, would only cost you about $36/year.
Obviously LN distribution isn't up to par with electricity, but in the "closer" term it certainly would be feasible for "industrial" applications. Like running the Internet backbone routers.
Re:Gift for understatement (Score:5, Informative)
Back in the 80s, I remember LN pricing (in commercial/industrial quantities) being around $0.05 per liter (roughly $0.20 per US gallon). This FAQ [interesting-products.com] suggests that the price is now around $0.50 per gallon in quantity.
Re:Gift for understatement (Score:4, Funny)
Back in the 80s, I remember LN pricing (in commercial/industrial quantities) being around $0.05 per liter (roughly $0.20 per US gallon). This FAQ [interesting-products.com] suggests that the price is now around $0.50 per gallon in quantity.
...which makes it significantly cheaper than gasoline. Here's a thought: I wonder how much energy is released as it boils, and how that compares to a gasoline combustion engine. Sure, maybe we'd need more liquid volume, but it's cheaper per unit volume... and its not a Greenhouse gas either - it's 79% of the atmosphere already!
Re:Gift for understatement (Score:5, Informative)
Just answered my own question [washington.edu]...
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Kool! {grin}
At least there will be no problem with air conditioning.
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Just answered my own question...
Which proves an important Slashdot axiom: If you think the parent post might be a "whoosh joke," first check to see if the University of Washington has already implemented it. If they have, then you know it is.
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I wonder how much energy is released as it boils
I'm sorry about bursting your bubble, but its boiling is a result of its change of state: it is not releasing mechanical/thermal energy into the environment, but rather receiving thermal energy from a hotter thermal bath (at room temperature).
Also, don't forget that you'd spend more energy taking heat off a volume of nitrogen (or oxygen, or other gas for that effect) to liquify it. I'm not fully aware of the details (too lazy now to look into Wikipedia, go figure...), but I believe it involves using machine
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Wow. The electrical bill savings could pay for the LN2.
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I don't like liquid nitrogen. It hurts my teeth.
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I'd think that they would become useful first in places that are already using superconductor devices, like medical sensors and photo sensors.
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Never done much overclocking and had reason to investigate the alternative cooling systems that requires, like oil or water cooling or piezoelectrics? Those present substantial maintentance and disaster possibilities that are enough to scare away all but the most determined. It's not when fun when your water-cooling system springs a leak and wrecks components (both from direct water damage and from heat damage from the loss of necessary cooling).
Having LIQUID NITROGEN in my desktop PC would seem to presen
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what if the enclosure ruptures and explodes like a capacitor?
Why would it do such a thing? I don't see much resemblance between a computer case and a capacitor, and you can have liquid nitrogen in the open air without any sort of explosive effects. I mean, I'm no expert, so I could be totally wrong but...
What if it leaks nitrogen into the room and asphyxiates my cat sleeping on the floor?
I really can't see how this would happen either. About 80% of the air you breath is nitrogen. Nitrogen is lighter than ox
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I'm not saying such a system would necessarily be feasible or practical, but calling it dangerous seems like a stretch.
The liquid propane tanks we all have for our grills are a hell of a lot more dangerous.
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1 liter of LN2 is about 800 grams. Molar mass of N2 is 28g/mol, so 1 liter of LN2 is about 28 moles.
1 mole of ideal gas takes about 22.4 liters at STP, so 28 moles will displace about 600 liters of air. Not nice.
Oh, and the first sign of hypoxia is loss of consciousness.
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600 liters is bearly enough to cover you floor
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Nope. All gases mix freely in all proportions.
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Wait... have I forgotten basic chemistry? I thought nitrogen was heavier than air?
[Checks old CRC Handbook, Googles....]
Ooops! I must have confused it with CO2, shame on me. Okay, so my second scenario isn't gonna happen, but I think the first one is still possible. I wouldn't wanna mess with it, and I'm no stranger to chem hacking and modding and overclocking. The consequence-benefit ratio just doesn't promote it very well.
Re:Gift for understatement (Score:5, Interesting)
Having LIQUID NITROGEN in my desktop PC would seem to present maintenance and disaster potential an order of magnitude greater than that: what if the enclosure ruptures and explodes like a capacitor? What if it leaks nitrogen into the room and asphyxiates my cat sleeping on the floor?
Years ago, I did Unix administration for the School of Science for a small university. The server room was behind the NMR lab (with its large superconducting magnets) and I had to go through the NMR lab to get to the sever room. In fact, the sever room was also used to store a 100 litre tank of LN and 100 litre tank of LH. The tanks will not explode. In fact, they leak a tiny amount of nitrogen and helium all the time. Even in the closed sever room (it had its own AC, seperate from the building AC), this was not a problem.
Also, a PC is not like a superconducting magnet: It will not 'quench' and cause the LN to rapidly evaporate. Even if it did, a PC is not going to contain much LN - less than 1 litre. A magnet (at least back then) would have 50 (or more) litres of LN (and LH). The affect on a the nitrogen level of the 20x20 room was negligible, even at floor lever. And, if your PC did quench, the noise of the escaping gas would almost certainly wake your cat or dog (with the likely size of the relief orifice in the PC would result in a piecing ultrasonic whistle, which cats and dogs cat hear).
(FWIW, the most, be far, dangerous aspect of a magnet quench is the helium. But that clings to the ceiling. Being cold, it also condenses water vapor, forming a cloud.)
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He's concerned about the safety of using a supercooled computer to control his home fast-breeder reactor
non-computing has use for it (Score:3, Interesting)
Think of power converters. Think of a broadcast TV transmitter.
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"Only drawback is they need to be supercooled, something that may be addressed by improving the materials used." - that last part is a bit of an understatement. We're still decades (centuries?) away from room temperature superconductors [wikipedia.org].
Even getting it up to liquid nitrogen temperatures would probably be "good enough" for non-portable uses. I'm pretty sure that's a heck of a lot cheaper than liquid helium.
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Re:Gift for understatement (Score:5, Informative)
so they are not used for very large magnets.
The wire drawing issue doesn't exactly help, but the main reason is Type I [wikipedia.org] vs. Type II [wikipedia.org] superconductors - the low-temperature metallic superconductors have a kind of superconductivity (Type I) that doesn't break down even in quite strong magnetic fields. However, the liquid-nitrogen (relatively-)high-temperature ceramic superconductors lose superconductivity (Type II) beyond a certain field strength. Which is very bad if you're using them for magnetic resonance imaging or particle acceleration (note how the LHC failure involved liquid helium cooling) which depend on generating and switching really strong magnetic fields generated by superconducting supermagnets, but doesn't matter so much if you're using them for computing or power transmission (with due care and attention to the strength of magnetic fields to avoid sudden catastrophic breakdown...).
Re:Gift for understatement (Score:5, Informative)
You're half right.
Two facts:
1) all superconductors superconduct better at lower temperatures
2) all superconductors superconduct better at lower magnetic fields
Basically, you can think of it as both temperature and magnetic field introducing a kind of disorder (causing Cooper pairs [wikipedia.org] to break up, destroying superconductivity).
Type I superconductors don't allow any magnetic fields, Type II allow up to certain field strengths, depending on the material and also on temperature. (This is a 'competition' between the two important length scales in a superconductor: the coherence length--size of a Cooper pair; and the penetration depth--up to which distance a magnetic field still penetrates into the material).
In fact, the most important drawback of the high-temperature superconductors (up to about 140K), is that at those higher temperatures they don't allow for high magnetic field nor high current. Also, they're hard to produce on a large scale. Still it's commercially viable these days to use superconductors for current transport at liquid nitrogen temperatures.
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They only need to be room temperature for 'consumer' grade computers.
Re:Gift for understatement (Score:4, Interesting)
That all depends on what you consider 'room temperature'. To me, that doesn't mean actual room temperature, it means a temperature that can be achieved with small, economical cooling systems. I could see all the way down to -50 degrees C being practical for in home use. Considering the record for superconductivity is around -135 C, we're really not all that far away. In fact, seen as liquid nitrogen is relatively cheap to produce, if transistors existed above that temperature it would be possible to begin large scale experimentation now.
Also, it's important to keep in mind that we don't have a working theory for how the newer higher temperature superconductors work. It's within the realms of imagination that when we finally come up with an explaination, research will proceed much more rapidly. The highest temperature superconductors known today were found essentially by trial and error.
Bad timetable. (Score:5, Interesting)
We have no idea how far away we are. We don't fully get it and are pretty much trying substances at random. We might figure out something that works next year or never. It's not something you can predict with any accuracy.
Re:Bad timetable. (Score:5, Funny)
So you're saying we could have something to market in 5 but possibly up to 10 years?
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Exactly. All we need is a couple basic elements to work out the kinks... like a cheap high temperature superconductor.
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A small pinch of unobtainium will certainly help.
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We have no idea how far away we are. We don't fully get it and are pretty much trying substances at random. We might figure out something that works next year or never. It's not something you can predict with any accuracy.
So, what you're saying is that we're still at the Thomas Edison stage.
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OK, so we submerge the entire PC into some sort of super cold, non conductive substance. So just how fast would a super cold, quantum computer compute? Would I finish writing its software before I began or would the software vanish as soon as i peeked at its output?
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New Sensationalist (Score:2, Insightful)
"Only drawback is they need to be supercooled, something that may be addressed by improving the materials used." - that last part is a bit of an understatement.
Is an understatement from the New Sensationalist (as it should properly be called) an oxymoron?
The New Sensationalist runs a story every couple of weeks about how some new breakthrough will revolutionize something or other in the next two years. Has anyone gone through their predictions like we do with psychics to see what their actual hit rate really is?
Other than that, how was the play Mrs. Lincoln? (Score:2)
That's like saying, "I have a cancer cure pill that works 100% percent of the time and costs mere pennies per pill, with no patents! Oh, one minor hitch, my revolutionary "cyanide pill" tends to kill the host, but we're optimistic on a workaround!"
Sounds like something you'd say to investors to raise capital, not to peer scientists, or know-it-all
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"Only drawback is they need to be supercooled, something that may be addressed by improving the materials used." - that last part is a bit of an understatement. We're still decades (centuries?) away from room temperature superconductors [slashdot.org].
Which just means that we need a room-temperature semiconducting superconductor! Or, do I mean a room-temperature superconducting semiconductor?
Ah hell, I don't know what I mean.
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How cold is space?
Sounds like it would be ideal for spacecraft.
Liquid cooling? (Score:5, Funny)
At 0.3 kelvin - just above absolute zero - these electrons flow without resistance and so create a superconductor.
So my stock fan won't quite cut it this time?
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Re:Liquid cooling? (Score:5, Funny)
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Fans don't make a whooshing sound... so what's your point? ;)
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Whoosh!
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Whooosh!
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touche
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Re:Liquid cooling? (Score:5, Informative)
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<McKay>Shut up, Nye!</McKay>
Besides, all we have to do is pump the heat into another universe through a wormhole bridge!
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I think the parent's point is that if you put a fan in an isolated box, the average temperature inside the box will increase.
Of course that if you have cold air somewhere you can move it using a fan to decrease temperature in another place. Or you can remove warm air as long as you have a source of colder air available.
And of course that moving air can aid you at lowering your body temperature by assisting you in transpiration.
The parent is just being pedantic.
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Well, I know one slashdotter that hasn't been reading the marketing materials. Jeesh!
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I suppose if it blows hard enough it might push the electrons faster~
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I suppose if it blows hard enough it might push the electrons faster~
That's what she said...
Yeah, and if she's blowing she's not doing it right.
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So my stock fan won't quite cut it this time?
No problem. Just get one of these [hpd-online.com] at your neighborhood Fry's. Vacuum pumps and hardware are not included.
Daisy, Daisy, Give me your answer do... (Score:2)
Perhaps this discovery is just one more step in the direction of a singing homicidal AI computer.
Daisy, Daisy
Give me your answer do
I'm half crazy
all for the love of you...
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... now including more death!
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blend (Score:1, Funny)
but will it blend?
Not really news (Score:4, Informative)
Josephson Junction has been used for switching in superconductors since I was a kid.
http://en.wikipedia.org/wiki/Josephson_effect
Neat, yes, but not really the first (Score:3, Informative)
As far as I know, the first superconducting transistor was reported in 2006:
cond-mat/0601434 [arxiv.org]
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WOW (Score:2)
Wow! thats super c... uggh... forget it
The overclockers ... (Score:2)
How much energy to keep postage area supercooled? (Score:1)
If we use our best insulators like aerogel or some vacuum flask? Can it be done?
Wasn't there a story somewhere... (Score:2)
...about liquid-cooled laptops? I've a feeling someone's about to make a joke about that and this story...
College dorm dream (Score:2)
Everyone had that dream in college. Build a liquid nitrogen cooled computer at 4Ghz in your dorm room while you could still use all the electricity you wanted. Even 10 years later that's still an untouchable speed for consumers.
Speed??? (Score:5, Insightful)
Speed isn't only determined by on-state resistance. Capacitance & inductance matter too and will be the limiting factors for a theoretical transistor that's 0 resistance on and infinite resistance off. Such a theoretical transistor won't dissipate heat, so it won't get hot. However, heat will be dissipated somewhere else because current still must flow from high potential to low potential. Furthermore, transition times aren't arbitrarily fast, and during the transition, the transistor will dissipate resistive power; this could be a big problem for systems cooled below 4 K.
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I was wondering about something similar myself:
Apparently (and I could be wrong), the cooling isn't necessary because of the amount of heat generated, but because the properties to achieve super-conducting require super-cooling to achieve zero-resistance.
Whereas, my understanding of today's computers is that we cool them to lower increasing resistance due to heat.
So the former is cooling before the fact, and the latter is cooling after the fact (I think).
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You're forgetting that since superconducting components have a negligible resistance you need negligible potential differences to achieve the same current. In fact, for a true super conductor it is impossible to have a stable high potential difference across it (since it would imply infinite current through it ). You can turn them into solenoids to get an impedance for oscillating currents, a
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It all depends on what your application is. You can store energy in a magnet with virtually no loss, and you can probably make an oscillator where charge bounces around between gates for a very long time. However, if you want to switch transistors on demand, it's going to be hard to manage things without sending that charge to a lower potential. Feynman analyzed the thermodynamics of computation, and it does require a finite amount of energy.
Anyhow, it's not like anybody is actually going to use these tran
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Anyhow, it's not like anybody is actually going to use these transistors for computation anytime soon. If they're used at all, it will be for front-end amplifiers for cryogenic detectors.
National spy agencies will probably find a use for them.
FETs are tricky (Score:3, Interesting)
We'd love to get our hands on some superconducting FETs. The ones I'm designing around right now have 5 milliohms Rds, and they're *still* getting so hot we have to solder big heat sinks onto the backsides of them.
But this just shifts the problem to the gate drive, because during any finite time period between 'off' and 'on' the FET acts like a big power resistor and heats up. Even if people ever make these so they're superconducting at room temp, they'll still heat up when in the active region. (Or we'd need to develop drivers that could produce instantaneous off/on transition times.) So we'd need ones that could remain superconductive in well over room-temp transients. If you have a superconducting FET that suddenly stops superconducting because of a temperature peak, it'll vaporize just about instantaneously. These would be an exciting gamble.
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One thing that I recently learned is that in the context of a power converter, the diode will actually induce loss in the fet, and that will usually be the main contributor of loss. Of course there is a tradeoff between on resistance and gate capacitance, but it is important to pick good fast diodes to minimize loss.
If you are just making a load switch however, and are losing power to ohmic loss then you are stuck with picking a better package or paralleling them for better net on resistance. D2PAKs are goo
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I'm using a Vishay PolarPAK -- astoundingly low Rdson, great power-handling, but a bear to solder. I'm working with switching boost and buck controllers, so these are the FETs they're controlling.
Paralleling works, but then you have higher gate capacitance, and that brings its own problems. Grumble.
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Something doesn't sound right to me... it sounds like you're suggesting that the heat is from simple resistive losses, not switching losses.
If you need to actually solder big heatsinks to a FET (as opposed to bolting on a reasonbly-sized unit), that makes me think we're talking about 100 watts or more of power dissipation... which at, say, 10 milliohms (because nobody ever gets that the datasheet lists), would be 100 amps of current. and let's face it, when you have to run 2-gauge conductors to your FETs,
Why this is important (Score:1)
80 watts for 80K (Score:3, Interesting)
Yes, you can insulate a device, so that in almost all cases (definitely in the case of a fast-switching transistor) the main heat source is the device itself.
Here's a commercial box [suptech.com] that cools a 2-inch wafer of high-temperature superconductor to around 80K. This box uses 80 watts including whatever other signal processing stuff is in there.
Another source (Cryogenics 42 (2002) 705-718) says that 1W of cooling power at 4K will cost you 5kW of input power using a straightforward helium compressor. This scales as 1/temperature^2 for higher temperatures, but for lower temperatures you'd switch to a different type of refrigerator.
0.3K refrigerators using helium 3 would not use more than 10kW, but this is already too much for most applications.
So the practical significance of this research is that it may be reproduced with higher temperature materials, not that we will build THz DSPs at 0.3K.
Superconductors cannot be supercooled (Score:5, Informative)
Use of the term "supercooled" in this context is bogus. Something is supercooled if it remains a liquid, even though it should be a solid at those conditions (or it remains a gas where it should be a liquid). If you put a glass of very clean distilled water in a freezer you'll find out that you can cool it down to -7*C or lower without freezing. It will momentarily freeze if you drop a snow flake into it though, or when you hit the glass with a screwdriver.
(For the curious: this is because extremely small crystals and droplets have higher free enthalpy than the bulk phase due to surface effects, so their formation is inhibited.)
This has nothing to do with superconductors, because they are always solids and cannot be supercooled. For superconductors you're looking for "cooled below its critical temperature", but I admit that it doesn't sound as good as "supercooled".
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I've had fun sticking bottles of water in the freezer, then pulling them out at just the right moment. They appear as liquid when I first pick them up, but then the whole thing turns to ice, starting at one end, in 5 seconds or less.
The resulting ice is soft, even fluffy, and is fun to munch on.
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This is known as the perfect temperature for beer consumed after mowing the lawn.
more drawbacks (Score:2)
The only drawback is not just supercooling.
Let's talk fabrication. Anyone know what the yields are on lanthanum aluminate? What are the physical manufacturing chanllenges?
Making one transistor is easy compared to making millions of billions (per die, per wafer, per lot) of them reliably and cost-effectively. That is the major obstacle. Remember how long it took to switch to copper wires in the late 1990's? And that was with billions of dollars invested by many companies, and in a hurry!
It took 40+ year
Size matters less (Score:2)
I say they can do it in 5.
Since reducing the fab size doesn't reduce resistance, it won't speed up a superconductive processor. If someone is willing to put up with a system size of a fridge, or entire building (and keep it cold), it will work just fine, potentially at speeds that are orders of magnitude above modern supercomputing. I very much doubt that this will ever see a consumer desktop, or even many server rooms. But anybody already in the supercomputing business would probably be happy to go thro
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Paying more attention now, this is liquid helium cooled, not liquid nitrogen, that makes getting this cost effective a harder problem, since a bigger size would be much more expensive to maintain.
First Superconducting Transistor (Score:1)
Cooper pair transistor (Score:1)
You know, it's almost as if you all have never heard of the Cooper pair transistor:
http://www.google.com/search?q=cooper+pair+transistor [google.com]
Waidaminute, you're joking... (Score:2)
You can make a superconductor by supercooling a conductor? Holy crap. What a breakthrough!
Glassy Metals? (Score:1)