Prof. Moshe Ben Shalom
School of physics, Tel Aviv University, Israel
Switching the response of crystalline matter is a key challenge in the development of next-generation electronic and functional materials. A direct and efficient approach to modifying material properties is to induce controlled shifts in atomic positions, altering the underlying symmetries. However, structural rearrangements are typically constrained by strong interatomic bonds, limiting most current technologies to electronic reconfigurations without atomic displacement.
In this context, layered van der Waals (vdW) crystals offer a unique advantage, as their weak interlayer interactions enable structural lubricity and atomic-scale displacements with minimal energy input. Notably, we have demonstrated electric-field-driven atomic shifts in a two-atom-thick artificially assembled ferroelectric crystal, enabling polarization switching at the nanoscale (Science, 2021). Expanding this concept, to multi-layered structures we discovered internal polarizations that accumulates linearly with the number of layers and co-exsisting with an in-plane conductivity (Nature, 2022). After refining the underlying structural switching mechanisms (Nature Reviews Physics, 2024), we proposed a novel device concept to control polytype transitions with outstanding percisions and effichiency (Nature, 2025).
The talk will explore the diverse landscape of vdW polytypes, their stacking-dependent orbital overlaps, characteristic adheasion energies, discrete symmetries, and overall properties. Finally, I will outline our ongoing efforts to expand the "Slide-Tronics" paradigm, leveraging sliding-induced phase transitions for novel applications in nanoelectronics and beyond.