Affiliation:
1. Sun Yat-sen University
Abstract
Abstract
The emergence of magnetic transition metal dichalcogenides has significantly advanced the development of valleytronics due to the spontaneous broken of time reversal symmetry and space inversion symmetry. However, the lack of regulation method has preventing researchers from exploring their potential applications. Herein, we propose to use the strain engineering to control the spin-valley coupling in the sliding ferroelectric bilayer H phase VX2 (X = S, Se, Te). Four multiferroic states are constructed by combining the sliding ferroelectricity and antiferromagnetism in the R-stacking bilayer VX2, where the spin and valley polarizations are coupled together from the layer-dependent spin-polarized band structures. By applying a small external strain or pressure on the out-of-plane van der Waals direction, we predicted that there is an antiferromagnetic to magnetic transition in the bilayer VX2, leading to interesting spin-polarized chiral circularly polarized radiation at K+ and K− valley, similar to those found in the magnetic monolayer. To comprehend the coupling between various degrees of freedom in these multiferroic systems, we have developed an effective k·p model. This model unveils a linear relationship between the electric polarization generated by interlayer sliding and the valley energy difference at the valence band maximum. Thus, providing an alternate method to measure the electric polarization in the sliding ferroelectrics. Based on the strong coupling between the strain, spin-valley and electric polarization, it is likely to use the strain to control the interesting emerging properties of H phase VX2 such as the anomalous valley Hall effect.
Publisher
Research Square Platform LLC