Atomic hard drive

A prototype atomic-scale computer hard drive has been made to work at room temperature, reaching the limits of what researchers think is possible in data storage.

Applied to a PC, the technology would allow hard drives to hold more than a million times the amount of information than can be stored on a CD-ROM – more than could be read in a lifetime.

Developed by scientists at the University of Wisconsin, the breakthrough could lead to substantial advances in the miniaturisation of computer data storage technology. The microscopic hard drive is constructed on a silicon wafer that is covered first in gold, then in silicon atoms. The silicon atoms are aligned in furrows made by the gold, and are manipulated by a scanning tunnelling microscope.

The microscope writes the data on to the disc atom by atom, using 20 atoms to store one bit of information, including the space around the atoms. It stores the data digitally, using the presence of atoms to signify a one and the lack of atoms as a zero.

While a CD-ROM holds 650Mb, every square centimetre of the drive would hold 9,800 gigabytes. Like a conventional hard drive the device could be formatted, written and read at room temperature. Previously similar techniques have been successful only at very low temperatures.

Hewlett-Packard has also made advanced in storage capacity. It claims that with a process similar to lithography, already used for chip manufacture, it can store 12.5 gigabytes per square centimetre of disc – about 7,800 times less than the atomic system. The company says the storage system could be on sale soon.

Wisconsin lead researcher and physics professor Franz Himpsel is more cautious about when his prototype could be developed for commercial use, however. ‘It will be 30 years before this could be a hard drive you could buy for your computer. ‘But with Moore’s Law, the exponential shrinking and subsequent increase in performance, it is possible,’ he said.

Himpsel said the technology is primarily one for storage, not computer memory. The slow speed at which the drive records data means that it cannot be used for random access memory.

The lack of speed is due to the limitations of the scanning tunnelling microscope. Improved electronics could increase the STM’s speed fivefold according to Himpsel, but it would still be slower than today’s hard drives.