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Researchers Put 'Spin' in Silicon
ccellist writes "Physorg.com is reporting on the University of Delaware and Cambridge NanoTech's experiments regarding 'spintronics,' or the ability to use information about electron spin in atoms of silicon to encode information, much like we use information about an electron's charge state in computers today. 'Spintronics' research hopes to usher in a new age of computer speed and performance by measuring and even controlling the angular momentum displayed by all electrons, and using this information to encode data. Researchers for the first time have successfully conducted the spin of electrons in a custom-made silicon chip, a process known as 'spin transport.'"
This sort of physics is actually pretty easy to comprehend, so I'm not sure how it could be twisted.
Basically, we can think of an atom as a sea urchin. So around this atom, we have a number of spikes. These can be considered the electrons of the atom. Now, this is a major simplification of Schroedinger's equation, but essentially each spike represents the probabilty of locating an electron within a volume of space.
Now, these spikes come in pairs, in order to balance each other. They're on opposite sides of the sea urchin atom. They slide around the atom, but they're always opposite to one another. This is typically called the Pauli exclusion principle by physicists.
So to an external viewer looking at the atom, it appears as though the spike pairs are spinning around the circumference of the atom. Relative to the viewer's position, these spike pairs are moving either clockwise or counterclockwise around the atom. This is how we get the two different spins, which thus can be used to repesent binary information.
Now, when you're dealing with larger atoms, with many electron pairs, the interaction between the electrons leads to a greater degree of electron stability and predictability. Thus electron pairs will still spin around the atom, but they'll travel in a path that's actually quite consistent, relative to the other electron pairs. By focusing only on certain electron pair paths, and the direction that they spin around the atom relative to the viewer's position, we can store large amounts of binary data per atom.
nah, it's all appropriate. The angular momentum is on the magnetic moment produced at the electron from an applied magnetic field, due mainly to the Zeeman interaction. The spin itself is the magnetic moment of the electron. Changes in the magnetic field (non parallel) apply a torque on the moment and change its orientation. The motions are described by the quantum angular momentum equations .. i.e. commutation relations. These commutation relations are the quantum analog to the classical angular momentum equations.
Unfortunately, the "hilarious" joke is on you, since spin actually does refer to angular momentum. It can even be interchanged with "orbital" (extrinsic) angular momentum while obeying momentum conservation, and (as the article mentions) can be measured using a magnetic field.
A quick look at wikipedia before posting is usually helpful.
Man, there are so many errors here I don't know where to begin. The Electron-Volt (eV) is a unit of energy (the work required to move an electron across a potential different of one Volt). Digital computers do not depend on the magnitude of the current, but on its abssence or presence. In fact, the goal is to have as little current as possible (less losses due to heat and radiation) -- we are nearing single-electron transistors. "Spintronics" would instead carry the information in the spin state (up or down) of an electron. The reference to "charge" probably stems from memory, where information is stored in the magnetization state of a small amount of matter.
Here is a better explanation. This topic has been covered before many times.
I D=959FBD96-E7F2-99DF-341F959A7DA2A292&chanID=sa003
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http://scientificamerican.com/article.cfm?article
http://www.sciam.com/article.cfm?articleID=0007A7