Ferroelectricity-driven metallicity and magnetic skyrmions in the van der Waals Cr2Ge2Te6/Hf2Ge2Te6 multiferroic heterostructure

Two-dimensional (2D) multiferroic heterostructures present a promising platform for advanced spin devices by leveraging the coexisting ferromagnetic and ferroelectric orders. Through first-principles calculations and atomistic simulations, we reveal nonvolatile control of metallicity and topological spin textures in the ${\mathrm{Cr}}_{2}{\mathrm{Ge}}_{2}{\mathrm{Te}}_{6}/{\mathrm{Hf}}_{2}{\mathrm{Ge}}_{2}{\mathrm{Te}}_{6}$ (CGT/HGT) heterostructure. Notably, manipulating ferroelectric polarization in HGT significantly modulates the magnetic anisotropy energy and Dzyaloshinskii-Moriya interaction of CGT/HGT, reversing the easy magnetization axis from in plane to out of plane. By analyzing the atomic-resolved spin-orbit-coupling energy ($\mathrm{\ensuremath{\Delta}}{E}_{soc}$), it is found that the cause of the change comes from the Fert-Levy mechanism. Additionally, this polarization control enables the creation and annihilation of bimerons and skyrmions, with interlayer sliding further altering magnetic ordering. Our findings offer valuable insights into magnetoelectric coupling and spin texture manipulation in 2D magnets, highlighting their potential for next-generation spintronic and memory devices.