Researchers have stored and read out a kilobyte’s worth of data using the world’s smallest hard disk – a speck of copper that stores the bits on chlorine atoms – and they say the technology could someday hold vast amounts of data in a minuscule space.
The team says they reached a storage density of 500 trillion bits per square inch, which is 500 times better than the best commercial hard disk currently available.
“In theory, this storage density would allow all books ever created by humans to be written on a single post stamp,” Sander Otte, a researcher at Delft University’s Kavli Institute of Nanoscience in the Netherlands, said in a news release.
The technique is described today in a paper published online by Nature Nanotechnology.
The team used the needle on a scanning tunneling microscope to push the chlorine atoms around on the copper surface.
“You could compare it to a sliding puzzle,” Otte said. “Every bit consists of two positions on a surface of copper atoms, and one chlorine atom that we can slide back and forth between these two positions.”
The atom’s position effectively represents a binary code of zero or 1, and the matrix of atoms is such that the bit’s position is stable.
As a proof of principle, Otte and his team encoded 160 words from quantum physicist Richard Feynman’s famous 1959 lecture, “There’s Plenty of Room at the Bottom.”
In that lecture, Feynman speculated on the frontiers that could be opened up if atoms could be arranged one by one to encode information. The researchers did just that, on a copper grid measuring about 100 nanometers wide. They also used the device to store a similarly sized section of text from Charles Darwin’s “On the Origin of Species.”
Otte emphasized that atomic-scale memory devices won’t be available anytime soon.
“In its current form, the memory can operate only in very clean vacuum conditions and at liquid nitrogen temperature (77 Kelvin, or 321 degrees below zero Fahrenheit), so the actual storage of data on an atomic scale is still some way off,” he said. “But through this achievement we have certainly come a big step closer.”
In a Nature Nanotechnology commentary, Steven Erwin of the Naval Research Laboratory also noted that encoding and decoding the information is slow. It took one or two minutes to write the data to each 8-by-8-atom block, and about 10 minutes to read out the information from each block using the scanning tunneling microscope.
Nevertheless, Erwin said the achievement was significant – and would, “at the very least, stimulate our imaginations towards the next such milestone.”
Meanwhile, other teams of researchers are working on DNA-based data storage devices that can be chemically tweaked, molecule by molecule, to store information almost as densely. This month, computer scientists at the University of Washington and Microsoft announced that they were able to store 200 megabytes of data in a smidgen of DNA.
In addition to Otte, the authors of “A Kilobyte Rewritable Atomic Memory” include F.E. Kalff, M.P. Rebergen, E. Fahrenfort, J. Girovsky, R. Toskovic, J.L. Lado and J. Fernandez-Rossier.