Strain-engineered topological phase transitions in ferrovalley 2H−RuCl2 monolayer

Distinct ferrovalley characteristics of the Janus RuClX (X = F, Br) monolayer

“…Moreover, the geometric structures at 6 ps maintained their integrity, which demonstrates the thermal stability of the RuClX monolayer. Compared with the D 3h symmetry of the RuCl 2 monolayer, 30 the symmetry of the present Janus RuClX monolayer was reduced to C 3v . The symmetry-breaking of C 3v may produce interesting results, such as a higher T C in the VSSe monolayer 27 and greater piezoelectricity in the Janus MXY (M = Mo or W, X/Y = S, Se, or Te) monolayer.…”

“…29 This interesting work showed that the T C was approximately 197 K with a U eff of 2.5 eV, and demonstrated the importance of electronic correlation and perpendicular magnetic anisotropy for ferrovalley materials. By first-principles calculations and Monte Carlo simulations, Sheng et al predicted a ferrovalley 2H-RuCl 2 semiconductor with out-of-plane magnetization and a high T C of 260 K. 30 Our group also found that halogen ions can modify the magnetic anisotropy and T C of rare-earth-based 2D FM monolayer GdX 2 (X = Cl, Br, I) semiconductors. 31 According to available reports, 2D Janus ferrovalley materials consisting of various halogen ions can be used to simultaneously achieve a high T C beyond atmospheric temperature, perpendicular magnetic anisotropy, and large valley polarization for future spintronic and valleytronic applications.…”

Effects of crystal deformation on spin-valley interplay and topological phase transition: a case study on VSi2X4 (X = N or P) monolayers

“…The generality of crystal deformation effects is also well displayed in other valley systems in previous studies. For example, biaxial strains can induce valley flipping and topological phase transition in both RuCl 2 56 and RuBr 2 57 systems. Besides, the application of crystal deformation and level regulation can drive the system from the ferro-valley phase into a valley-half-metal state as shown in Fig.…”

Correlation-driven topological phase transition in 2D valleytronic materials: a mini-review

“…24–26 In practice, the electronic correlation can be equivalently tuned by strain engineering, and then topological phase transition can be induced. 18,25,27–29 In this mini-review, we will introduce some recent progress in these special 2D valleytronic materials from a theoretical perspective.…”