Can Information Be Stored on a Single Atom?
IBM Breakthrough Advances Nanotechnology Research
As the computer industry continues chasing Moore's Law and components continue to shrink, the march continues to the inevitable end point: the atom. IBM researchers say they now have made a significant breakthrough that brings the industry a step closer to that end point.
In an article that will be published Sept. 24 in Science magazine, IBM researchers are outlining a new technique that can measure how long a single atom can hold data, and that enables scientists to record, study and visualize the magnetism of these atoms at extremely fast speeds.
Using IBM's STM (Scanning Tunneling Microscope) in a fashion similar to a high-speed camera, researchers at IBM Research's Almaden Lab can study the behavior of atoms at a speed 1 million times faster than before.
This ability to record and study atom behavior at nanosecond speeds opens up several avenues of research for the scientists because they now can add time as a dimension in their experiments. The results of all this could impact everything from solar cells to quantum computing to nanoscale data storage capabilities.
"If you take Moore's Law to the end, where you end up at is the atom," Andreas Heinrich, IBM Research staff member and group leader of nanoscale science at the Almaden Lab, said in an interview with eWEEK, adding that the question then becomes, Can you do computing and other work at that scale? "If you can do this, you reach ... not only for IBM, but for the entire industry, the holy grail."
IBM scientists have been using the STM for two decades to study matter at the atomic scale, which Big Blue officials said could lead to innovations around computing and data storage. With the new technique using the STM, researchers can study the behavior of atoms at the nanosecond level, whereas before it was at the millisecond level, Heinrich said.
That's important, according to IBM. The difference between a nanosecond and a second is equivalent to the difference between a second and 30 years, according to company officials. Now, because of the new technique, scientists can see the physics that happens during that time that they couldn't have seen before.
"What this breakthrough is really about is [moving from] milliseconds to nanoseconds," Heinrich said.
"This technique developed by the IBM Research team is a very important new capability for characterizing small structures and understanding what is happening at fast time scales," Michael Crommie, professor of physics at the University of California Berkeley and a faculty researcher at the Lawrence Berkeley National Labs, said in a statement. "I am particularly excited by the possibility of generalizing it to other systems, such as photovoltaics, where a combination of high spatial and time resolution will help us to better understand various nanoscale processes important for solar energy, including light absorption and separation of charge."
Previously, scientists had determined that an iron atom could hold data for a nanosecond. Now, with the new STM technique, they found that when putting a non-magnetic copper atom next to the iron atom, that iron atom could retain data for up to 200 nanoseconds. Being able to see that change means that scientists can now experiment to see how they can impact the behavior of atoms to get desired results.
According to IBM, the breakthrough could impact quantum computers, which are systems that aren't bound by the binary nature of traditional computers. Gaining a greater understanding of the nature of atoms could lead to researchers being able to perform advanced computations that currently aren't possible.
Can Information Be Stored on a Single Atom?
In the data storage arena, now that scientist can essentially see an atom's electronic and magnetic properties, they can study whether information can reliability be stored on a single atom.
IBM scientists were able to develop a new technique for the STM that enabled it to record the behavior of atoms stroboscopically, similar to how the first movies were created or to time-lapse photography. This was needed because the magnetic spin of an atom changes too fast to measure directly using the STM, according to the company.
Researchers use a "pump-probe" measurement technique, where a fast voltage pulse excites the atom. Then a weaker voltage pulse measures the nature of the atom's magnetism at a certain time after the excitation. The time delay between the two pulses creates a time frame of each measurement. The delay is then varied, and the average magnetic motion is recorded in small time increments. Taken together, the recorded increments give the scientists a more complete picture of the magnetic motion of the atom, similar to how a series of incremental photos can create a motion picture.
For each time increment, the alternating pulses are repeated about 100,000 times, which takes less than a second.
IBM scientists used iron atoms that were put onto an insulating layer one atom thick and supported on a copper crystal and position next to non-magnetic copper atoms. The structure was then measured when in the presence of different magnetic fields, which showed that the speed at which they changed their magnetic orientation depends on the magnetic field. Essentially, the scientists found that the atom's magnetism can reverse direction without having to go through intermediate orientations.
Knowing this, researchers may be able to engineer the magnetic lifetime of the atoms to make them longer-to retain their magnetic state-or shorter-to switch to new magnetic states-as needed.
"This breakthrough allows us-for the first time-to understand how long information can be stored in an individual atom, Sebastian Loth, at IBM Research, said in a statement. "Beyond this, the technique has great potential because it is applicable to many types of physics happening on the nanoscale."
IBM Research's Heinrich said it is far too early to tell if or how this will result in productized technologies. It will probably take another two to five years to determine whether atoms can be manipulated to store data for hours or days, rather than nanoseconds, and even longer-15 years or more-to determine whether any of this research will result in products. Finding that out is the goal, he said.
"Jumping to the scale of a single atom, that is clearly at the end of the road map," Heinrich said.