强THz场下GaAs和InSb中瞬态谷间散射和碰撞电离

摘要

运用系宗蒙特卡罗法计算了强THz场作用下,n型掺杂的GaAs和InSb中随时间变化的散射机制以及载流子非线性动力学演变,获取了电子散射至卫星谷并弛豫回原能谷的时间信息,并追踪描绘了载流子瞬态增加的过程,结果同时显示了强场作用下谷间散射是GaAs中的主要散射机制,而碰撞电离则是InSb中的关键因素.此外进一步讨论了这两种机制对于相关物理量:平均动能、平均速度、材料的电导率的影响,结果说明这两种机制导致了非线性效应并在两种材料中起到相反的作用,InSb中碰撞电离的响应时间比GaAs中谷间散射的响应时间更长.该研究结果在THz调制领域有一定的指导意义.%The ensemble Monte Carlo method was used to calculate the time-variation of scattering mechanisms and the carrier nonlinear dynamics evolution of n-doped GaAs and InSb in the high terahertz (THz) field.The time information of the electrons scattering into the side valleys and that of the electrons relaxation back into the original energy valley was directly obtained.The carriers transient increase process was also traced.Meanwhile,it showed that the intervalley scattering is the main mechanism of GaAs,while the impact ionization is a key point for InSb in high THz field.Furthermore,the work discussed the influences of the two mechanisms on related physical quantities:average kinetic energy,average velocity,and material conductivity.It indicates that the two mechanisms lead to nonlinear effects and play inverse roles in the two materials.The response time of impact ionization in InSb is longer than that of intervalley scattering in GaAs.The results have some guiding values in THz modulation field.