Twisted oxide membranes: Moiré induced polar topologies

03.06.2025 13:00 – 14:30

The recent realization of freestanding membranes of perovskite oxides, has enabled their deterministic mechanical assembly into twisted homo bilayers. Twisted oxide membranes surpass the limitations of epitaxial growth, which lock the direction of the crystalline axes of the growing layer, and open the way to a completely new generation of interfaces. In this talk I will show that twisted interfaces of transition metal oxides feature a non homogeneous pattern of shear strains determined by the atomic registry though the strong ionic bonding of this family of compounds. Twisted membranes unlock a “chirality” degree of freedom opening an unprecedented opportunity to tailor topological polar landscapes in a way determined by the lateral strain modulation driven by twisting [1]. We find that the peculiar pattern of polarization vortices driven by strain gradients through flexoelectric coupling of strain gradients to polarization are an indirect measure of the interlayer interaction which can be modulated by inserting graphene layers in between of the twisted layers. This finding opens exciting opportunities to manipulate the remote moiré interaction between the layers allowing for the exploration of novel physical effects and functionalities.

[1] G. Sanchez-Santolino et al. Nature 626, 529 (2024)

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Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre