In this work, we investigate the low-energy bands of monolayer WS₂ under external electric and magnetic fields using an effective low-energy Hamiltonian. Our calculations indicate that band gap of monolayer WS₂ increases linearly with an external perpendicular electric field and when the electric field energy ${\mathrm{\Delta }}_z$ is equal to the size of spin splitting, the band gap including spin–orbit interaction of the monolayer increases to its band gap as the case of without spin–orbit interaction. In the presence of the magnetic field, spin splitting energy in the conduction and the valence bands at the valleys depends strongly on the magnetic field. In this work, the optical properties of monolayer WS₂ are also calculated by using the Ehrenreich–Cohen formula. Our estimation for the square of the interband matrix element for transitions near the K points is in good agreement with previous calculations.

在这项工作中，我们使用有效的低能量哈密顿量研究了外部电场和磁场作用下单层WS ₂的低能带。我们的计算表明，单层WS _2的带隙随着外部垂直电场和电场能量的增加而线性增加。${\mathrm{\Delta }}_{ž}$等于自旋分裂的大小，与没有自旋轨道相互作用的情况一样，包括单层自旋-轨道相互作用的带隙增加到其带隙。在存在磁场的情况下，传导中的自旋分裂能和波谷处的价带在很大程度上取决于磁场。在这项工作中，还使用Ehrenreich-Cohen公式计算了单层WS ₂的光学性质。我们对在K点附近过渡的带间矩阵元素的平方的估计与以前的计算非常吻合。