Time-resolved studies of ultrafast electronic processes in two-dimensional solids in the strongly non-thermal regime

在提出的项目中，我们的目标是研究模型型二维材料系统在强亚7飞秒激光脉冲激发期间和激发后不久，即在强非热区的初级电子过程的动力学。在研究中，我们将重点研究石墨化材料(石墨烯和石墨)以及半导体过渡金属二卤化物MoTe2。在这两种石墨化体系的情况下，我们的目标是详细研究载流子-载流子相互作用和载流子-声子相互作用对光激发后前50fs内电子气内部热化的影响。关于过渡金属二卤化物MoTe2，该项目将重点放在带重整化效应和明显的Mott跃迁的动力学上，这两者都与建立屏蔽有关，因为导带被强烈的激发脉冲瞬时填充。这些研究将通过一个特别设计的时间和角度分辨光电发射实验进行，该实验能够探测超快过程，时间分辨率为&lt；10fs，接近傅里叶极限。这些规范将使我们能够直接监测所涉及的电子、声子和激子自由度的特征能级在与所述问题相关的极短时间尺度上对电子结构的瞬时变化的印记。

Within the proposed project we aim for studying the dynamics of primary electronic processes in model-type two-dimensional material systems during and shortly after excitation by an intense sub-7 femtosecond laser pulse, i.e. in the strongly non-thermal regime. Within the studies we will focus on graphitic materials (graphene and graphite) as well as the semiconducting transition metal dichalcogenide MoTe2. In the case of the two graphitic systems we aim for studying in detail the impact of carrier-carrier interaction and carrier-phonon interaction onto the internal thermalization of the electron gas within the first 50 fs after optical excitation. Regarding the transition metal dichalcogenide MoTe2 the project will focus on the dynamics of band renormalization effects and a conspicuous Mott-transition, both associated with the built-up of screening as the conduction band is transiently populated by an intense excitation pulses. The studies will be conducted with a specifically designed time- and angle-resolved photoemission experiment capable of probing ultrafast processes with a time resolution < 10 fs and near the Fourier-limit. These specifications will enable us to directly monitor the imprint of the characteristic energy scales of the involved electronic, phononic and excitonic degrees of freedom onto the transient changes of the electronic structure on the extremely short timescales relevant for the addressed problems.