Femtosecond dynamics in layered materials

该项目旨在研究层状材料中的超快电子动力学，范围从具有原子厚度的二维系统到拓扑绝缘体和非常规超导体，其中二维电子气体的维度和微观物理起着关键作用。这个研究课题需要在超快光谱技术方面取得重大进展，并开发一种新的装置来研究脉冲光激发驱动的飞秒动力学。对层状材料物理学的特别兴趣与它们的特殊特性有关，这些特性可以在光电子和电子的单原子厚器件中进行技术开发，从而克服当前半导体技术的小型化限制。对发生在这个维度尺度上的电子-电子和电子-声子散射机制等基本过程的全面研究，要求实现一种超快光谱系统，该系统具有极高的时间分辨率，结合了广泛的光谱覆盖和卓越的灵敏度。特别是，我们将专注于在不同光谱范围内产生超短光脉冲，用于双色泵浦探针实验，目标是获得低于10-fs的时间分辨率。高重复率将确保对少数/单层材料产生的小信号的敏感检测。利用该项目开发的新型光谱工具，将有可能揭示二维系统中光学和电子特性基础上的最终电荷动力学。

This project aims at the study of ultrafast electronic dynamics in the class of layered materials, ranging from two-dimensional systems with atomic thickness to topological insulators and nonconventional superconductors where dimensionality and the microscopic physics of two-dimensional electron gases play a key role. This research topic will require significant advances in ultrafast spectroscopy techniques and the development of a new setup for the study of femtosecond dynamics driven by impulsive photoexcitation. The particular interest in the physics of layered materials is related to their peculiar characteristics that can be technologically exploited in mono-atomically thick devices for optoelectronics and electronics, thus overcoming the miniaturization limitations of current semiconductor technologies.A full study of the fundamental processes, such as electron-electron and electron-phonon scattering mechanisms occurring at this dimensional scale, calls for the implementation of an ultrafast spectroscopy system capable of extreme temporal resolution combined to broad spectral coverage and exceptional sensitivity. In particular, we will focus on the generation of ultrashort optical pulses in various spectral ranges to be employed in two-color pump-probe experiments with the goal to obtain sub-10-fs temporal resolution. High repetition rate will ensure sensitive detection of the small signal arising from few/mono-layered materials. With the novel spectroscopic tools developed in the project, it will be possible to unveil the ultimate charge dynamics that are at the basis for the optical and electronic properties in 2-dimensional systems.