Sliding into novel materials: A new frontier in material science
by Erica Marchand
Paris, France (SPX) Feb 06, 2025
Can copper be turned into gold? While ancient alchemists pursued this elusive goal, modern science knows such a transformation requires nuclear reactions. However, some materials, like graphite and diamond, share the same atomic composition-pure carbon-yet differ vastly due to atomic arrangement. While converting graphite into diamond demands extreme heat and pressure, a more practical material transformation is now being explored at Tel Aviv University.
Led by Prof. Moshe Ben Shalom, head of the Quantum Layered Matter Group, and PhD students Maayan Vizner Stern and Simon Salleh Atri from the Raymond and Beverly Sackler School of Physics and Astronomy, the research focuses on manipulating graphite’s atomic layers through weak van der Waals forces. Their findings, recently published in Nature Review Physics, suggest that by carefully shifting these layers, materials with novel electronic properties can be created.
Though this technique won’t produce diamonds, a rapid and efficient sliding process could serve as the foundation for ultra-small memory units in electronic devices. Such “polytype” materials could potentially surpass the value of gold and diamonds in technological applications.
PhD student Maayan Vizner Stern explains, “Like graphite, many natural materials have weakly bonded layers. Each layer acts like a LEGO brick-difficult to break, but easy to separate and reconnect. These layers naturally prefer specific stacking positions where atoms align precisely with adjacent layers. Sliding between these positions occurs in discrete jumps, shifting by just an atomic distance at a time.”
Her colleague, PhD student Simon Salleh Atri, elaborates, “We are devising new ways to manipulate these layers and study the resulting materials. By applying an electric field or mechanical pressure, we can shift layers into various stable configurations. Once the external force is removed, the layers remain locked in their final position, effectively storing information and functioning as tiny memory units.”
The research team is also investigating how the number of layers influences a material’s properties. For instance, when three layers contain two types of atoms, six distinct stable materials emerge, each with unique internal polarizations. With five layers, the number of possible structures increases to 45.
By selectively switching between these configurations, electrical, magnetic, and optical properties can be precisely controlled. Even graphite, despite being composed solely of carbon, can rearrange into six distinct crystalline forms, each exhibiting different electrical conductivities, infrared responses, magnetizations, and superconducting properties.
A major challenge remains: ensuring stability while allowing controlled transitions between these atomic configurations. The team’s latest perspective paper outlines current studies and introduces novel techniques to refine the “Slidetronics” mechanism, potentially leading to groundbreaking developments in electronics and computing.
As research progresses, these sliding materials could revolutionize technology by enabling faster, more efficient memory storage and granting unprecedented control over material properties. Rather than creating gold, scientists may soon uncover something even more valuable-the ability to engineer materials at the atomic level, unlocking untapped potential in the world of material science.
Research Report:Sliding van der Waals polytypes
Related Links
Tel-Aviv University
Space Technology News – Applications and Research
