FERRERO · Computational design of sliding ferroelectrics and multiferroics from van der Waals materials

The increasing needs of our society and the growing energy consumption call for inventing ultra-fast and power-saving electronic devices capable of integrating different functionalities in the same physical space. Ferroelectric materials, whose electric polarization can be switched reversibly, seem to be pivotal for the development of electronics, offering non-volatile, high-speed writing at low voltage and high endurance. However, they should also enable a non-destructive readout, for example, via a spin-orbit or a magnetic detection of state. Multiferroics with coupled ferroelectric and magnetic orders seem optimal for the electric writing and magnetic read-out but they are very scarce. With FERRERO, I will design sliding ferroelectrics and multiferroics that can be artificially created by stacking van der Waals (vdW) materials. While 2D materials offer unlimited possibilities of design, the mechanism of ferroelectric switching via interlayer sliding of two monolayers ensures very low switching barriers and room-temperature operability. In addition, vertical stacking of 2D magnets could give rise to magnetoelectric coupling allowing for the control of the magnetic state via electric polarization. The twisting of two layers with respect to each other induces a moiré superlattice with strongly correlated bands, providing an extra knob to control ferroelectricity, spin-orbit effects, and magnetism. I plan to (i) develop and implement several computational tools and combine them all together in the open-source publicly available code to enable fast and accurate calculations of moiré materials, (ii) simulate several non-twisted and twisted vdW bilayers to understand the mechanism of ferroelectric switching and unveil the strength of the magnetoelectric coupling, and (iii) explore sliding ferroelectric and multiferroics for electronic devices allowing for energy-efficient and ultra-fast data writing, and the construction of cascaded circuitry.