Ferroelectrically controlled topological magnetic phase in a Janus-magnet-based multiferroic heterostructure

Electric control of topological magnetic phases has attracted extensive attention due to its potential applications in energy-efficient spintronic devices. Here, using first-principles calculations and atomistic spin model simulations, we demonstrate that electric control of topological magnetic phases can be realized in Janus-magnet-based multiferroic heterostructure, i.e., ${\mathrm{MnBi}}_2{\mathrm{Se}}_2{\mathrm{Te}}_2$/${\mathrm{In}}_2{\mathrm{Se}}_3$. The loops of vortices and antivortices can be transformed into skyrmions with diameter of only 4 nm via ferroelectricity reversal, which is originated from the change of magnetic anisotropy. For heterostructure with up polarization, loops of vortices and antivortices are further tuned to bimeron solitons by applying in-plane magnetic field. Our results thus pave the way for achieving highly tunable topological magnetism in atomic-thickness heterostructure, which can be useful in nonvolatile data encoding and storage with low-energy consumption.

Figure 1

Top and side views of the crystal structure of (a) MBST and (b) ${\mathrm{In}}_2{\mathrm{Se}}_3$. (c) Side views of MBST/$P\uparrow$ and MBST/$P\downarrow$ HSs. Green, purple, blue, brown, and red balls represent Se, Bi, Mn, Te, and In elements, respectively. The orange vectors in (c) indicate two spin configurations with opposite chirality used to extract the in-plane DMI strength.

Figure 2

Layer-resolved localization of the SOC energy difference $\mathrm{\Delta }{E}_{\mathrm{soc}}$ between opposite chiral spin configurations in MBST (black bar) monolayer, MBST/$P\uparrow$ (red bar) and MBST/$P\downarrow$ (blue bar) HSs.

Figure 3

The spin textures for MBST monolayer, MBST/$P\uparrow$ and MBST/$P\downarrow$ HSs in real space. Corresponding external fields are labeled above each panel. The color map indicates the out-of-plane spin component of Mn atoms.

Figure 4

Spin textures of (a) MBST monolayer under in-plane magnetic field of 30 mT and (b) MBST/$P\uparrow$ HS under IP magnetic field of 40 mT. The color map indicates the OOP spin component of Mn atoms.

Figure 5

(a) Layer-resolved MAE of MBST/$P\uparrow$ and MBST/$P\downarrow$ HSs. (b), (c) MAE coming from $5p$ orbitals hybridization, and (d), (e) projected density of states of Te which is adjacent to Mn atom in MBST/${\mathrm{In}}_2{\mathrm{Se}}_3$ HS.

Figure 6

Planar-average charge-density difference of MBST/$P\uparrow$ (left panel) and MBST/$P\downarrow$ (right panel) HSs. The blue and black dots represent the positions of MBST and ${\mathrm{In}}_2{\mathrm{Se}}_3$ atoms, respectively.

Figure 7

Calculated phonon band structure for the MBST monolayer.

Figure 8

(a) The evolution of total energy and (b) temperature during the ab initio simulations for MBST monolayer at 300 K. The (c) top and (d) side views of MBST supercell after simulations of 10 ps.

Figure 9

Top and side views of 12 stacking configurations for MBST/${\mathrm{In}}_2{\mathrm{Se}}_3$ HS s.

Figure 10

Total energies of 12 stacking configurations for (a) MBST/$P\uparrow$ and (b) MBST/$P\downarrow$ HSs. The dashed line indicates the most stable stacking.

Figure 11

Three different spin configurations applied to calculate the NN and NNN exchange coupling parameters.

Figure 12

The orthorhombic unit cell for MBST and MBST/${\mathrm{In}}_2{\mathrm{Se}}_3$ HSs. The purple atoms represent Mn element.

Figure 13

The spin textures for MBST monolayer with λ in range of 0.1 to 0.4. The color map indicates the out-of-plane spin component of Mn atoms.