Scientists have discovered a new class of materials that could lead to improvements in computer memory.
The team examined structures in which different materials were deposited in layers a few atoms thick. They discovered that these layered heterostructures boast something very useful: ferroelectricity.
Ferroelectric materials exhibit spontaneous electric polarization, with a positive electric charge on one side of the material and negative on the other. This polarization can be reversed by applying an electric field. And the two possible polarization orientations can correspond to 0 or 1, making them useful for computer memory.
"Our discovery shows a possibility that researchers could engineer properties at the atomic scale and create new, artificial materials exhibiting novel functional properties not existing in their constituents," says University of Nebraska-Lincoln physicist Evgeny Tsymbal.
"This significantly broadens the class of known ferroelectric materials and provides possibilities to design new ferroelectrics."
The scientists fabricated their heterostructures by depositing atomic layers of different materials, layer-by-layer, in stacks of thickness of a few nanometers. Although neither of the constituent materials was ferroelectric, the composed heterostructures were.
Excitingly, the new materials also exhibit magnetoelectricity: a change in electric polarization through the application of a magnetic field.
"This functionality is especially interesting because of potential application in electrically-controlled data storage with significantly reduced energy consumption," says Tsymbal.