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Contributed Speaker

Prof. Moshe Ben Shalom

School of Physics and Astronomy, Tel Aviv University, Israel

Sliding vdW polytypes

 

A direct way to switch crystals' properties is to move the relative atomic positions and change the underlying symmetries. However, the challenge of breaking solid interatomic bonds confines current technologies to switch electronic states without moving the atoms. The structural rearrangement challenge is naturally addressed in Layered van der Waals (vdW) crystals with relatively weak vdW attractions between successive layers. In response to external electric fields, the layers exhibit discrete sliding steps between different meta-stable configurations of periodic crystals with distinct symmetries. These 2D vdW polytypes are metastable, exhibit diverse electronic/optical/magnetic properties, and are free to switch via super-lubricant sliding of incommensurate partial dislocations lines. The talk will review our recent observation of interfacial ferroelectricity in sliding vdW polytypes by Kelvin Probe Force microscopy.