A group of researchers has demonstrated for the first time a single-molecular electret, a device that may be one of the keys to creating molecular computers. The new development is reported by Nature Nanotechnology.
Smaller electronics are critical for the development of better computers and other devices. Scientists are looking to find a way to replace silicon chips with molecules. Of course, this includes the creation of a single molecular electret, a switching device that could serve as a platform for extremely small non-volatile memory devices. However, experts were confident in the instability of such a device and generally wondered if it would ever be invented.
And yet, along with international colleagues, Mark Read, professor of electrical engineering and applied physics, demonstrated a single molecular electret with functional memory.
Most electrets are made from piezoelectric materials, such as those that produce sound in speakers. In an electret, all dipoles – pairs of opposite electric charges – spontaneously line up in the same direction. Using an electric field, you can change their direction.
“The question has always been how small these electrets could be made, which are essentially memory devices,” explains Reed.
The researchers inserted a gadolinium (Gd) atom inside a carbon buckyball, a 32-sided molecule also known as buckminsterfullerene. When scientists placed this structure in a transistor-type structure, they saw the transfer of one electron and used this to understand its energy state. The real breakthrough was the discovery that an electric field can be used to switch an energy state from a stable state to something else.
“This molecule acts as if it had two stable states of polarization,” explains Reed.
“We have proven that it is possible to create two states in a molecule that cause spontaneous polarization and two switchable states,” the author of the study concludes. “And this can lead to new ideas. For example, to shrink memory to literally a single molecular level. Now that we understand that this is possible, we can move on to new developments”.