Photoinduced phenomena originated from electron geometrical phases

对于二维拓扑绝缘体和三维拓扑绝缘体上的表面态，我们证明了连续激光可以控制电子和自旋霍尔电流。这些现象的基本物理原理是，激光场的应用将电子跳跃能量转化为变量，因此，由给定材料参数唯一固定的拓扑不变量反过来又成为外部可控变量。因此，我们可以预期在适当的条件下量子化的电子和自旋霍尔电流可以被光致。

For two-dimensional topological insulators and a surface state states on three-dimensional topological insulators, we demonstrated that an electron and spin Hall current can be controlled by an application of continuous laser beam. Underline physics of these phenomena is that the application of the laser field turns a electron hopping energy into a variable, and thus topological invariants that are uniquely fixed by given material parameters in turn become externally controllable variables. Consequently, we can expect quantized electron and spin Hall current can be photo-induced under an appropriate condition.