Femtosecond dynamics in layered materials

该项目旨在研究分层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。本研究课题将需要在超快光谱技术和脉冲光激发驱动的飞秒动力学研究的新设置的发展显着的进步。对层状材料物理学的特别兴趣与它们的独特特性有关，这些特性可以在光电子学和电子学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。对基本过程的全面研究，例如在这个维度尺度上发生的电子-电子和电子-声子散射机制，要求实现能够结合宽光谱覆盖和异常灵敏度的极端时间分辨率的超快光谱系统。特别是，我们将专注于在各种光谱范围内的超短光脉冲的产生，用于双色泵浦探测实验，目标是获得亚10 fs的时间分辨率。高重复率将确保对由少量/单层材料产生的小信号的灵敏检测。随着该项目中开发的新型光谱工具，将有可能揭示最终的电荷动力学，这些动力学是二维系统中光学和电子特性的基础。

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.