强太赫兹激光和磁场辐照下极性半导体及低维系统中类氢杂质电子态变化特征研究

The experimental research on variation characteristics of hydrogenic impurity state in polar semiconductors and low dimensional systems, which simultaneously subjected intense terahertz laser and magnetic field, has attracted widespread attention. However, the corresponding theoretical study on shallow impurity state is still in the preliminary exploring stage, there isn't sufficient theory about it.The dressed-atom approach treating intense laser field effect via dressed Coulomb potential and dressed confined potential, and the dressed-band approach including intense laser radiation through the renormalization of the semiconductor energy gap and conduction/valance effective masses, two of them are current main theoretical methods. However, their application scopes not only have some limitations but also cannot be used to treat the case of Faraday geometry.Thus,this project will study the physical properties of shallow impurity states in polar semiconductors and low dimensional systems simultanesouly subjected intense terahertz laser and magnetic field, the concrete content includes:(1) A extended time-dependent nonperturbative theory on the basis of nonperturbative treatment for intense laser effect is proposed to study the binding energy of shallow impurity, and further investigating the shallow impurity states along with structural parameters and external field conditions about the change rule. (2) A time-dependent perturbative theory based on Dyson series is proposed to study multi-photon assisted resonant magnetopolaron effect on shallow impurity, and seeking the deep relations among resonant magnetopolaron effect on shallow impurity states，structural parameters, and external field conditions. (3) Analyzing the dependence of the lifetime of hydrogenic impurity states on structural parameters and external field conditions. (4) Performing a comprehensive analysis of the physical properties of shallow impurity states, and further revealing how structural parameters and external fields to modulate and optimize it through changing external conditions.

强太赫兹激光和磁场辐照下极性半导体及低维系统中类氢杂质电子态变化特征的实验研究引起了广泛关注，但理论研究还处于初步探索阶段,没有形成完善的理论体系。将光场作用包含在缀饰势的缀饰原子法,以及重整化到能带带隙和有效质量的缀饰能带法，是目前主要的理论方法。但该理论适用范围存在局限性，也不能处理法拉第位形。因此，本项目将针对强太赫兹激光和磁场辐照下极性半导体及低维系统中类氢杂质电子态变化特征开展以下工作:(1)基于我们完善的严格考虑强激光效应的含时非微扰理论，发展扩展含时非微扰理论并用于研究类氢杂质电子束缚能，揭示与结构参数和外场条件的变化规律；(2)基于戴森级数发展处理含时微扰的含时微扰理论，研究类氢杂质电子多光子协助的共振磁极化子效应，探寻与结构参数和外场条件的深层关系；(3)研究类氢杂质电子态寿命与结构参数和外场的依赖性；(4)综合分析杂质电子态物理特性及结构参数和外场条件对它的优化与调控。

在过去几十年中，强太赫兹激光和磁场辐照下极性半导体及低维系统中类氢杂质态的变化特征引起了科学家广泛兴趣。但是，目前理论研究还处于初步探索阶段，没有形成完善的理论研究体系。因此，我们针对强太赫兹激光和磁场作用下半导体系统中类氢杂质态的物理性质进行了深入研究。首先，我们发展了普适的理论方法——含时非微扰理论和含时微扰理论，即完善了理论体系；其次，将该理论研究了强太赫兹激光和磁场作用下，不同位形的半导体和量子阱中类氢杂质态的非单调的物理性质。研究表明法拉第位形下，强外场能增强或减弱缀饰库仑势，相对于类氢杂质静态束缚能杂质态束缚能发生蓝移或红移，并观察到了回旋共振效应。但在沃伊特位形下，缀饰库仑势只在z方向被增强，所以只有2p_z态束缚能发生蓝移或红移，其余的杂质态束缚能只发生红移。类氢杂质态束缚能随半导体结构参数(杂质位置、势阱宽度、势阱深度)也具有上述类似的变化规律。此外，类氢杂质基态衰减率在太赫兹量级，所以受激杂质电子的动量和能量弛豫过程受到强太赫兹激光场的强烈修正，在强外场下多光子效应越来越显著；最后，将该理论研究了不同位形下多光子协助的共振磁极化子效应。研究表明在非极化子共振区域，包含光子过程的磁极化子能级修正与不包含光子过程的磁极化子能级修正类似，并在法拉第位形观察到了回旋共振效应。同时在极化子共振区域，观察到了伴随多光子过程的磁极化子能级修正和共振磁极化子效应。强外场可调制多光子协助的共振磁极化子效应并使它们远离剩余辐射带，这将为测量电子-声子相互作用提供新途径，也为强外场调控的新型光电子器件提供理论支持。目前，本项目已发表了4篇论文(3篇SCI)，2篇论文已被接收(1篇SCI和1篇EI)，已投稿2篇论文（SCI），正在整理4篇论文（SCI）。