Crystal ‘domain walls’ may lead to tinier electronic devices
June 19, 2017
Queen’s University Belfast physicists have discovered a radical new way to modify the conductivity (ease of electron flow) of electronic circuits — reducing the size of future devices.
The two latest KurzweilAI articles on graphene cited faster/lower-power performance and device-compatibility features. This new research takes another approach: Altering the properties of a crystal to eliminate the need for multiple circuits in devices.
To do that, the scientists used “ferroelectric copper-chlorine boracite” crystal sheets, which are almost as thin as graphene. The researchers discovered that squeezing the crystal sheets with a sharp needle at a precise location causes a jigsaw-puzzle-like pattern of “domains walls” to develop around the contact point.
Then, using external applied electric fields, these writable, erasable domain walls can be repeatedly moved around in the crystal to create a variety of new electronic properties. They can appear, disappear, or move around within the crystal, all without permanently altering the crystal itself.
Eliminating the need for multiple circuits may reduce the size of future computers and other devices, according to the researchers.
The team’s findings have been published in an open-access paper in Nature Communications.
Abstract of Injection and controlled motion of conducting domain walls in improper ferroelectric Cu-Cl boracite
Ferroelectric domain walls constitute a completely new class of sheet-like functional material. Moreover, since domain walls are generally writable, erasable and mobile, they could be useful in functionally agile devices: for example, creating and moving conducting walls could make or break electrical connections in new forms of reconfigurable nanocircuitry. However, significant challenges exist: site-specific injection and annihilation of planar walls, which show robust conductivity, has not been easy to achieve. Here, we report the observation, mechanical writing and controlled movement of charged conducting domain walls in the improper-ferroelectric Cu3B7O13Cl. Walls are straight, tens of microns long and exist as a consequence of elastic compatibility conditions between specific domain pairs. We show that site-specific injection of conducting walls of up to hundreds of microns in length can be achieved through locally applied point-stress and, once created, that they can be moved and repositioned using applied electric fields.