论文标题
THZ辐射引起石墨烯中的圆形大厅效应
THz radiation induced circular Hall effect in graphene
论文作者
论文摘要
我们报告了后门提供的单层石墨烯中圆形横向terahertz光电导率的观察。光电导率响应是由自由载体吸收引起的，并在切换辐射螺旋时逆转其符号。观察到的直流霍尔效应表现出在没有磁场的情况下由圆形极化的Terahertz辐射引起的时间反转对称破裂。对于低栅极电压，发现光学信号与辐射强度成正比，并且可以通过THZ和静态电场的联合作用以及电子气体的动态加热和冷却来归因于电子力量的比对。令人惊讶的是，在高门电压下，我们观察到线性内强的霍尔光电导率消失了。低强度下的光响应变成了超线性，并且随辐射强度的平方而变化。我们将这种行为归因于辐射电场中二阶和四阶效应的相互作用，到目前为止尚未在理论上解决，需要进行其他研究。
We report on the observation of the circular transversal terahertz photoconductivity in monolayer graphene supplied by a back gate. The photoconductivity response is caused by the free carrier absorption and reverses its sign upon switching the radiation helicity. The observed dc Hall effect manifests the time inversion symmetry breaking induced by circularly polarized terahertz radiation in the absence of a magnetic field. For low gate voltages, the photosignal is found to be proportional to the radiation intensity and can be ascribed to the alignment of electron momenta by the combined action of THz and static electric fields as well as by the dynamic heating and cooling of the electron gas. Strikingly, at high gate voltages, we observe that the linear-in-intensity Hall photoconductivity vanishes; the photoresponse at low intensities becomes superlinear and varies with the square of the radiation intensity. We attribute this behavior to the interplay of the second- and fourth-order effects in the radiation electric field which has not been addressed theoretically so far and requires additional studies.
