A scientific breakthrough: Tel Aviv University researchers have created the world’s thinnest technology. It has a thickness of just two atoms. The researchers claim that the new technology can store electric information in the smallest unit of science known, in one of the most stable and inert materials. Quantum-mechanical electron tunneling through atomically thin films may allow for information reading that is much more advanced than current technologies.
Researchers from the Raymond and Beverly Sackler School of Physics and Astronomy and Raymond and Beverly Sackler School of Chemistry performed the research. Maayan Vizner, Yuval Waschitz and Dr. Wei Cao were part of the group. The article is published in Science magazine. We (and many others) work to predict and control the unique properties of these particles as they condense into an orderly structure we call a crystal. A tiny, crystalline device that switches between two states, such as “yes” or “no,” “up” or “down,” is at the heart of the computer. It is only possible to encode or process information with this dichotomy. The real challenge is finding a mechanism that allows switching in a small, fast, and affordable device.
The current state-of-the-art devices are made of tiny crystals with about a billion atoms. Each device switches back a million times per minute.
The researchers reduced the thickness of the crystal devices to just two atoms after this technological breakthrough. Dr. Ben Shalom explains that memories based on electrons’ quantum ability to hop through barriers as thin as a few atoms can be made with such a light structure. It may improve electronic devices’ speed, density, and energy consumption.
The researchers used a two-dimensional substance: one-atom-thick layers of boron nitrogen arranged in a repeating hexagonal structure. They broke this crystal’s symmetry by artificially adding two layers. Dr. Ben Shalom says that this material, in its natural three-dimensional form, is composed of many layers, each of which rotates 180 degrees relative to its neighbor (antiparallel configuration).
“In the laboratory, we could artificially stack the layers without rotation. This hypothetically places atoms of the same type in perfect overlap despite their strong repellence force (due to their identical charges). The crystal prefers to slide one side of the other so that half the atoms of each layer are in the perfect overlap. Bits that overlap are of opposite charges. All others are above or below the space, which is the hexagon’s center. These layers are very distinct in this artificial stacking arrangement. If, for example, the boron atoms are only present in the top layer, it is the opposite in the bottom layer.
Dr. Ben Shalom mentions the work of the theory group, which conducted many computer simulations. “Together, we established a deep understanding of why the system’s electrons arrange themselves exactly as we had measured them in the laboratory.” He says this fundamental understanding has led to fascinating responses in other symmetry-broken layer systems.
Maayan Wizner Star, a Ph.D. student, explained: “The symmetry-breaking we created in a laboratory, which is not present in the natural crystal, forces the electric charge to reorganize itself among the layers and make a tiny internal electric polarization perpendicular to the layer plane. If we apply an opposite electric field, the system will change its polarization orientation. Even when the external electric field is turned off, the switched polarization will not change. This is similar to the thick, three-dimensional ferroelectric system widely used in technology today.
Dr. Ben Shalom says, “The ability to force an electronic and crystalline arrangement in such a thin structure, with unique inversion and polarization properties resulting from weak Van der Waals forces among the layers, isn’t limited to the boron or nitrogen crystal.” We expect similar behaviors in many layers of crystals that have the proper symmetry. Slide-Tronics is a novel and efficient method to control advanced electronic devices. We have given it the name Slide-Tronics.
Maayan Stern concludes, “We are excited to discover what happens in other states that we force upon nature and predict other structures that couple more degrees of freedom. Miniaturization and flipping through slides will make electronic devices more efficient and, in the future, provide new ways to control information. This technology is expected to be used in detectors, energy storage, conversion, and interaction with light. As such, our challenge is to find more crystals with new, slippery degrees of freedom.