Tunable valley and spin splitting in 2H-VSe₂/BiFeO₃(111) triferroic heterostructures

The spin and valley degrees of freedom in monolayer transition metal dichalcogenides have potential applications in spintronics and valleytronics. However, nonvolatile control on the valley and spin degrees of freedom of two-dimensional ferromagnetic materials by multiferroic materials has been rarely reported. Here, the electronic structure of monolayer 2H-VSe2/BiFeO3(111) triferroic heterostructures has been investigated by first-principles calculations. It is found that the V magnetic moment, spin and valley splitting of monolayer VSe2 can be affected by the BiFeO3(111) substrate with ferroelectric polarization and G-type antiferromagnetic order. Particularly, the reversed orientation of ferroelectric polarization and magnetic order of the BiFeO3(111) substrate can modulate the magnitude of spin and valley splitting, and change the spin splitting direction and the spin-dependent valley state in the valence band of monolayer VSe2. The coupling among ferroelectrics, magnetism and ferrovalley is realized in 2H-VSe2/BiFeO3(111) triferroic heterostructures. These results provide a new platform for multiferroic regulation in spintronics and valleytronics, which can enrich the diversity for high-performance devices based on two dimensional multiferroic heterostructures.