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Major Breakthrough In Spintronics Research
Invisible Pink Unicorn writes "Spintronics is the field of research into developing devices that rely on electron spin rather than electron charge to carry information. A major advance has been made by the Naval Research Laboratory (NRL), where they have for the first time generated, modulated, and electrically detected a pure spin current in silicon. Progress in this field is expected to lead to devices which provide higher performance with lower power consumption and heat dissipation. Basic research efforts at NRL and elsewhere have shown that spin angular momentum, another fundamental property of the electron, can be used to store and process information in metal and semiconductor based devices. The article abstract is available from Applied Physics Letters."
This sounds like the type of thing that will work under laboratory vacuum conditions, but which
we are decades away from being able to implement usefully for any real world application.
Since they are using the angular momentum of electrons to register as a voltage for recognition,
how susceptible to interference is such a system? I would imagine simply shining a flashlight
on such a quantum circuit would affect the resultant output... unless I'm way off.
Any microminds care to shed some light on this?
Quantum Teleportation. It's all the rage in Los Alamos.
The game.
For some reason, the term "spintronics" makes me think of it as though this was a long series of ball bearings in physical contact with the adjacent ones, and using the rotational force of the starting point to rotate each ball bearing in an opposite direction as the ones they're in physical contact with... eventually transferring the rotation to the end point.
Is it simply a case that in spintronics that the electrons used to carry a current don't actually leave their respective atoms (as they do in AC and DC current), but are just being rotated faster/slower or alternating direction?
8==8 Bones 8==8
Er, I understand the derivation. I just think it's a silly word. How would one usefully distinguish what these folks are doing -- which as far as I can see just amounts to detecting an electric current in a funky magnetic way -- from working with polarized light, which is, forsooth, detecting the spin current carried by photons? Aren't they both "spintronics?"
I don't see the problem with "blogosphere," by the way -- the extra "o" is just added to make it roll off the tongue easier, and there's plenty of precedent for adding unobtrusive vowels to make combining forms (e.g. prefixes) out of nouns. Hence, Greek "psyche" (soul) becomes "psycho" with an extra "o" when put in front of words that begin with consonants, like "logia" (study) to get "psychology." Latin "crypt" (vault, cavern, from earlier Greek usage meaning secret) adds an "o" to become "crypto" when it's used as a prefix, as in "cryptogram" or "cryptofascist."
Thanks very much! Wish the PR release and abstract had been more informative.
What's the argument for there being potentially far less dissipative losses with pure spin currents, however? It's still going to interact with the lattice via spin-orbit and spin-spin coupling terms, no? You're still going to get resistive heating, no? Is it just the fact that the magnetic dipole interactions are much shorter range interactions than the Coulomb force? (Except wouldn't it be a screened Coulomb force in the lattice anyway?)
Spin-orbit can still be quite strong yes, but it is very dependant on the material. An interesting way to think about it is that when you have a standard piece of conducting material, it's not that there is no current flowing in it while it sits there not hooked up to a source; actually the electrons go all over the place inside the material. Current flows right to left, left to right, but it all balances out and there is no net current. Resistive heating only occurs when you have net charge current. In an ideal spintronics device you would have charged currents flowing just like in any other material, but there would be no NET charge current. The spin current can diffuse along your channel. Why is this better in terms of heat? I'd have to check, but I think you're on the right track with the magnetic dipole being much weaker than an electric monopole. 1/r^4 vs 1/r^2 IIRC. One of the major benefits occurs if you can pass a coherent spin current along a channel. This leads to the possibility of quantum computations involving spins.
The difference is that there's very little energy required to flip a spin. The energy losses (at least the unavoidable ones) in computation come from deleting information, for instance to delete a single bit signified by a bunch of electrons caught in some place you'd let them flow to the ground line. If the voltage difference was, say, 2V you'd lose 2 eV per electron. If the same electrons had the bit stored in their spins, the energy you'd lose could be orders of magnitude lower, quite possible milli- or microeV.
Any sufficiently advanced libertarian utopia is indistinguishable from government.
Or, just imagine an infinitely high frequency alternating current.
The "major breakthrough" label was only used in the slashdot article... not exactly anything to get worked up about...
Slashdot quality declines as the number of hot grits posts decreases. - Provolt's Law, Apr-09-2005
Comment removed based on user account deletion
"Spin" itself is essentially jargon. Why not break it down into, say, quantum point source angular momentum? You could apply that same process to most of quantum physics and thoroughly eliminate the possibility of getting anything done.
If you throw out the phrase to somebody who doesn't know what it is, then sure, you probably should have explained better, or expect to be asked for an explanation. Spintronics is a convenience. Do you really think that a bunch of researchers, who presumably work on this daily, are going to keep repeating "spin polarization currents in conductors and semiconductors"?
For that matter, do you really suppose your hypothetical grandfather would derive more useful information from the phrase "spin polarization currents in conductors and semiconductors" versus "spintronics"? At least "spintronics" would give him a fighting chance to make the connection with "electronics"...
Slashdot quality declines as the number of hot grits posts decreases. - Provolt's Law, Apr-09-2005