Researchers develop new information storage device
12 October 2015
Scientists from Kiel University and the Ruhr Universität Bochum have developed a new way to store information that uses ions to save data and electrons to read data.
The development could enable the size of storage cells to be reduced to atomic scale dimensions. But that is not the only advantage of the new technology, as the researchers report in the journal, Scientific Reports.
Standard memory devices are based on electrons which are displaced by applying voltage. The development of ever smaller and more energy-efficient storage devices according to this principle, however, is increasingly approaching its limits.
"Moving data between individual storage devices has now begun to take a not inconsiderable amount of time. Put simply: more is moved backwards and forwards than is calculated," says Kohlstedt. Researchers want to move away from charge-based storage and towards a type based on electrical resistance.
The component developed at the labs in Kiel and Bochum consists of two metallic electrodes that are separated by a solid ion conductor, usually a transition metal oxide. If a voltage is applied, the ohmic resistance of the storage cell changes. This is caused by oxidation and reduction processes on the electrodes, as well as ions within the layer between being displaced. The advantage is that cells that are constructed in this way are easy to produce and can be reduced to almost the size of atoms.
The scientists achieved a long storage time by setting the ion density in the cells precisely via the voltage applied. According co-researcher, Mirko Hansen. This was a big challenge because electronic and ionic effects need to be uncoupled in order to manage this.
"Electrons are roughly 1,000 times lighter than ions and so they move much more easily under the influence of an external voltage," he says. "We were able to successfully exploit this, whereby in our component, the ions are immovable for extremely low voltages, while the electrons remain mobile and can be used to read the storage status."
The researchers built an ion conductor, measuring just a few nanometres thick to utilise quantum-mechanical effects for the flow through the storage cells. "The tunnel effect enables us to move electrons through the ultra-thin layer with very little energy", says Kiel's Martin Ziegler.
Ions move within the storage cell at voltages above one volt while electrons move at voltages far below one volt. In this way, ions can be specifically used for storing and electrons specifically for reading data.
The researchers also reported that their research had another very interesting element. The new resistance-based storage devices could even simulate brain structures. Rapid pattern recognition and a low energy consumption in connection with enormous parallel data processing would enable novel computer architectures.