The super raman intensity induced by spin-orbit coupling effect in monolayer MoS2 and WS2 under varying pressures

Abstract

Transition metal dichalcogenides (TMDs) are regarded as an optimal material for investigating the quantum effect of Spin-orbit coupling (SOC). Although many experiments have measured the physical properties of TMDs materials, the influence of the SOC effect on these properties cannot be determined. Here, we selected monolayer MoS2 and WS2 to investigate their physical properties in both the normal and SOC systems under varying pressures. By comparing the calculated results, the SOC effect significantly influences the effective mass of electrons and holes in the material, it determines the conductive properties of the material. This effect exerts a major influence on the dielectric properties of the material, and also enhances the polarization rate. Meanwhile, we have revised the traditional formula for calculating the raman intensity of symmetric dielectric tensors. The discovery of the super raman intensity effect of TMDs materials induced by the SOC effect has been made. Furthermore, we have discovered and explained how to modulate the TMDs materials in the visible light range to transition into a plasma state at specific wavelengths under pressure, and also reveal the influence of pressure on the strength of characteristic raman modes. The findings of this study provide pioneering theoretical support for the realization of the super raman intensity effect through the quantum effect and pressure manipulation of materials into a plasma state.