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IBM Shrinks Bit Size To 12 Atoms
Lucas123 writes "IBM researchers say they've been able to shrink the number of iron atoms it takes to store a bit of data from about one million to 12, which could pave the way for storage devices with capacities that are orders of magnitude greater than today's devices. Andreas Heinrich, who led the IBM Research team on the project for five years, said the team used the tip of a scanning tunneling microscope and unconventional antiferromagnetism to change the bits from zeros to ones. By combining 96 of the atoms, the researchers were able to create bytes — spelling out the word THINK. That solved a theoretical problem of how few atoms it could take to store a bit; now comes the engineering challenge: how to make a mass storage device perform the same feat as scanning tunneling microscope."
Preface: I'm just a programmer nerd who reads slashdot. I have no idea what I am talking about.
I wonder if it would be possible to have data storage as an ionization of a solid in the normal operating range of tech (and probably small, like carbon) where ionized atoms represent one bits and non ionized represent zero bits, and you can read atoms in some rigid lattice where the ionized ones represent ones and the neutral atoms are zeroes. Yea, there are huge problems, like preventing electron shell state dropping and keeping the electrons off the negatively charged carbon, but it seems like it would be a great objective considering the smaller data storage type after atom ionization will be measuring quark states to represent multi valued data.
...once they have these new mass-storage devices, how can I turn it into a homebrew tunnel scanning microscope?
Now they just have to work on that random access time of 300000 milliseconds.
Should be easy, right?
There are theoretical limits to how much information can be stored in a molecule -- this given by the molar entropy, typically expressed in J/(K*mol). But it can also be expressed, more intuitively, as bits per molecule.
(Yes, you can convert between J/K and bits -- they measure the same thing, degrees of freedom.)
Per this table, iron has a molar entropy of 27.3 J/K*mol, or 4.73 bits/molecule.
IBM is claiming an information density of (1/12) bits/molecule, which is reasonable -- the thermodynamic limit is ~57x greater.
Information theory is life. The rest is just the KL divergence.
There's a better article here which includes some more information on the experiment. In particular the temperature was 0.5K.
Also the computerworld article claims that using an antiferromagnetic arrangement of atoms is an advantage because it pulls the atoms more tightly together. I'm not convinced that this is true but even if it is the effect would be completely negligible. The interesting aspect of this arrangement is that each atom cancels out the magnetic field of the atoms either side of it which should help with data stability (a similar effect is seen in perpendicular recording today).
Unrelatedly: have they/will they publish a paper on this? I can't find anything mentioning a paper in the press releases.
So there is even more headroom in the thermodynamic limit.
You know, when you are storing bits and you are already at 12, where can you go from there? Where?
No where.
Ours goes to 11.
One smaller.
THL phish sticks
Imagine having a hard disk with a capacity of 2,000 TB. Using a SATA 3.0 bus with a sustained maximum throughput of 600 MiB/s, it would still take over 37 days to read or write the entire device.
An actual STM instrument is pretty big. About the size of, say, a mini-fridge. But the majority of that is the computer to drive the system, the readout electronics, and the enclosure (to dampen out vibrations, establish vacuum, etc.). The actual readout tip is pretty small: a nano-sized tip attached to ~100 micron 'diving board' assembly.
A related problem with STM is that it's a serial process: you have a small tip that you're scanning over a surface. This makes readout slow. However in a separate project, IBM (and others) has been working on how to solve that: the idea is to use a huge array of tips that scan the surface in parallel (IBM calls it millipede memory). This makes access faster since you can basically stripe the data and read/write in parallel, and it makes random seeks faster since you don't have to move the tip array as far to get to the data you want. It increases complexity, of course, but modern nano-lithography is certainly up to the task of creating arrays of hundreds of thousands of micron-sized tips with associated electronics.
Using tip arrays would make the read/write parts more compact (as compared to having separate parallel STMs, I mean). The enclosure and driving electronics could certainly be miniaturized if there were economic incentive to do so. There's no physical barrier preventing these kinds of machines from being substantially micronized. As others have pointed out, the first magnetic disk read/write systems were rather bulk, and now hard drives can fit in your pocket. It's possible the same thing could happen here. Having said that, current data storage techniques have a huge head-start, so for something like this to catch up to the point where consumers will want to buy it may take some time.