Berkeley (CA) – Physicists at U.C. Berkeley have taken a big step in little computer research. The idea of individual atoms forming the basic binary bits in a digital computer might seem like a dream. But scientists are now able to physically observe and measure individual atomic spin. This could make the impossible more possible.
The idea of having individual atoms serve as the foundation of binary computers has much merit. Binary computers are simple to program and while it is unlikely we’ll eventually find that binary computing is even remotely efficient compared to what’s out there, the theory is within our grasp today. It’s just a matter of making it work.
Nearly all electronic devices today are binary based. There is a host of electronic circuitry inside of each device, and all of it is reliant upon tiny electric charges of either “on” or “off,” which equate to 1 or 0. The entire CPU inside of your desktop, notebook, cell phone or PDA computer, is comprised of little more than a series of wires, cells and transistors. Each of them conveys an electric charge, holds an electric charge, or allows an electric charge to pass through either right or left.
Spintronic devices would operate similarly. But the determination of the 1 or 0 state would be based on its spin. A “1” might spin flat while a “0” might spin up/down. An atomic lattice structure would then be superimposed to set and query the state of individual atoms, conveying their stored data to what would most likely be quantum compute engines. These would then process whatever is required and send it back with the new spins for storage.
It sounds rather cumbersome and even clumsy. A lot of work to manipulate some data. But, this kind of manipulation, while requiring many steps, would happen 10s of thousands of times faster than modern silicon-based semiconductors. And while it all sounds wonderful on paper, it is still theory with only infant research made toward practical application.
The research work can only be carried out in the lab. The operational environment is an ultra cold chamber at only 4.7 Kelvin (-451 degrees Fahrenheit, the negative equivalent of where books burn). The cold temperatures are required to slow atoms down and help them align properly and in an orderly fashion. Also, nanomagnets are used to create tiny magnetic fields which basically suspend everything for their experiments. The magnetic fields are incredibly small from our point of view, but compared to the experimental material’s size they represent very large and powerful magnetic forces which hold everything in place.
In order to make it all work, Michael F. Crommie, a UC Berkeley professor of physics, and his colleagues, took tiny copper substrates and placed small atomic islands (comprised of cobalt) on them. Next, they sprinkled iron (or chromium) atoms over the top and let them fall where they would. Then, using a new technique called “low-temperature spin-polarized scanning tunneling spectroscopy,” which is just a fancy name for a powerful microscope which can “see” the surface spin and electron density of an atom, their spin was observed. This works because what they were looking at are called “adatoms,” which are atoms not molecularly bonded to the surface. They are just resting there, held in place by the magnetic field. The adatoms are then capable of being manipulated to alter their spin, or observed to read their spin.
Research into this type of variable spintronics could help solve some problems encountered today for quantum computing. If, for example, two atoms could be setup to spin a particular way that is known, called an entanglement, then one of them could be acted on by a quantum computer. After processing, the state of the original could be compared to the state of the computed for the purpose of “reading the answer.” That is a very significant area of research right now and one which could benefit greatly from advances like these at UC Berkeley.
As with most areas of research there are no definitive answers as to how this will play out. Dr. Crommie and his colleagues are asking questions and then using experimentation to answer them. While this research could ultimately prove to be a key stepping stone in effective nanoscale, even quantum computers, that reality is not yet known. It’s just a possibility.
As a scientist told me during an interview recently when I was seeing possible future applications for his research and the eventual technology, he basically said “Rick, there are a hundred steps between where we are today and the devices you’re talking about. But yes, that is where we’re headed and when we get there this might’ve been the research which took us. That’s why we keep doing it.”