Ferroelectric switching at symmetry-broken interfaces by local control of dislocation networks*

Recently discovered interfacial ferroelectricity in bilayers of transition metal dichalcogenide films provide an opportunity to combine the potential of semiconducting ferroelectrics with the design flexibility of two-dimensional material devices. In this talk, I will discuss scanning tunneling microscopy experiments revealing ferroelectric domains in a marginally twisted WS₂ bilayer.

We show that by tuning the electric field under a scanning tunneling miscroscpe, one can achieve local control of the ferroelectric domains at room temperature. We discuss their reversible evolution using a string-like model of the domain wall network (DWN). We identify two characteristic regimes of DWN evolution: (i) elastic bending of partial screw dislocations separating smaller domains with twin stackings due to mutual sliding of monolayers at domain boundaries and (ii) merging of primary domain walls into perfect screw dislocations, which become the seeds for the recovery of the initial domain structure upon reversing electric field.