Scientists from University of Liverpool, together with fellow technologists from University College London and the University of Zaragoza in Spain, have been working together to come up with a way to induce and control a fundamental electrical switching behavior. This involves affecting the way electrons behave at the nanoscale. The research is significant for the future development of electronic storage devices.
The study involves the separation of an ultra-thin layer of rock salt material away from the surface of metallic copper, with the manipulations occuring at the atomic level. This process is achieved by including a verythin layer of copper nitride in order to produce a layer of “electric dipoles.” The orientation of these dipoles can then be altered by applying a speciifc electric field, which affects the dipole. An electric dipole is a separation of positive and negative charges.
Then aim of the research is to address an issue that arises when some materials are inverted. Here inversion can lead to the phenonomeon of electric dipoles being maninfest. This affects the electric field and makes the material ferroelectric. There is growing interest in ferroelectrics as a new form of high density data storage. One concern hampering development of these more sophistciated storage devices, however, is that the outer layers of a ferroelectric material can lose their ability to switch once they are part of an electrical circuit.
The new technique overcomes this by using two dimensional materials that are only a few atomic layers thick and which can be utilized to create a different kind of dipolar switching material.
These materials take the form of an atomically thin layer of nitrogen and copper (copper nitride) being placed onto the surface of a copper crystal. On top of this a thin layer of rock salt material, like sodium chloride together with potassium bromide is placed.
Speaking with Controlled Environments magazine, the lead researcher Professor Mats Persson, explains the significance further: “This is a very exciting development and contrary to traditional wisdom that it is possible to have ferroelectric-like behavior in atomically, thin layers in a metal-insulator junction.”
He adds: “By stacking two 2D materials, even those that are insulators, we can create new behavior that neither material would be able to exhibit individually. This opens a wealth of new possibilities for developing a new generation of 2D material structures.”.
The findings have been published in the journal Nature Nanotechnology. The research paper is titled “Electric polarisation switching in an atomically-thin binary rock salt structure.”
