“Technological breakthrough from Tel Aviv University
The innovative technology may significantly improve electronic devices in terms of speed, density, and energy consumption.
Thinnest Unit Known to Science
Researchers from Tel Aviv University have engineered the world’s tiniest technology, with a thickness of only two atoms. The new technology proposes a way for storing electric information in the thinnest unit known to science, in one of the most stable and inert materials in nature. The technology works by using quantum-mechanical electron tunneling, which through the atomically thin film may boost the information reading process much beyond current technologies.
The multidisciplinary research was performed by scientists from the Raymond and Beverly Sackler School of Physics and Astronomy and Raymond and Beverly Sackler School of Chemistry. The group includes Maayan Vizner Stern, Yuval Waschitz, Dr. Wei Cao, Dr. Iftach Nevo, Prof. Eran Sela, Prof. Michael Urbakh, Prof. Oded Hod, and Dr. Moshe Ben Shalom. The work is published in Science magazine.
Today’s state-of-the-art devices have tiny crystals containing about a million atoms (about a hundred atoms in height, width, and thickness). A million of these devices can be squeezed about a million times into the area of one coin, each device switching at a speed of about a million times per second. The researchers were now able, for the first time, to reduce the thickness of the crystalline devices to two atoms only, allowing information to move at a quicker speed.
Playing with Crystals
In the study, the researchers used a two-dimensional material: one-atom-thick layers of boron and nitrogen, arranged in a repetitive hexagonal structure. In their experiment, they were able to break the symmetry of this crystal by artificially assembling two such layers.
“In the lab, we were able to artificially stack the layers in a parallel configuration with no rotation, which hypothetically places atoms of the same kind in perfect overlap despite the strong repulsive force between them (resulting from their identical charges).” explains Dr. Ben Shalom. “In actual fact, however, the crystal prefers to slide one layer slightly in relation to the other, so that only half of each layer’s atoms are in perfect overlap, and those that do overlap are of opposite charges – while all others are located above or below an empty space – the center of the hexagon. In this artificial stacking configuration, the layers are quite distinct from one another. For example, if in the top layer only the boron atoms overlap, in the bottom layer it’s the other way around.”
Maayan Wizner Stern, the PhD student who led the study, adds that, “The symmetry breaking we created in the laboratory, which does not exist in the natural crystal, forces the electric charge to reorganize itself between the layers and generate a tiny internal electrical polarization perpendicular to the layer plane. When we apply an external electric field in the opposite direction the system slides laterally to switch the polarization orientation. The switched polarization remains stable even when the external field is shut down. In this the system is similar to thick three-dimensional ferroelectric systems, which are widely used in technology today.”
The team expect the same behaviors from many layered crystals with the right symmetry properties, and have dubbed the promising concept of interlayer sliding as an original and efficient way to control advanced electronic devices “Slide-Tronics”.
“We hope that miniaturization and flipping through sliding will improve today’s electronic devices, and moreover, allow other original ways of controlling information in future devices. In addition to computer devices, we expect that this technology will contribute to detectors, energy storage and conversion, interaction with light and more. Our challenge, as we see it, is to discover more crystals with new and slippery degrees of freedom.” concludes Wizner Stern.
The study was funded through support from the European Research Council (ERC starting grant), the Israel Science Foundation (ISF), and the Ministry of Science and Technology (MOST).”