Materials World Network: Electron-lattice dynamics at an atomically controlled buried interface

两个半导体之间的内部界面由化学键和电子态组成，它们与材料的本体和表面有明显的不同。在这个项目的框架内，我们计划通过时间分辨、相干声子光谱来研究与这种界面相关的振动激发的动力学。GaP/Si（001）将作为一个模型系统。极性半导体GaP和非极性半导体Si具有相似的晶格常数，但电子和声子性质不同。该项目的主要目的是实验检测界面特定的振动激发及其性质与界面原子结构的相关性。在外延生长过程中，通过不同的参数对其进行修饰和控制，并通过扫描透射电子能谱对其进行原子分辨率的结构表征。相干声子光谱学特别适合于研究电子和声子激励的动态耦合。因此，预计计划中的实验也将提供有关埋藏的内部半导体界面的电子激发动力学和电荷转移过程的有趣信息。

The internal interface between two semiconductors consists of chemical bonds and electronic states that can differ distinctively from those of the bulk and the surface of the materials. In the framework of this project we plan to investigate the dynamics of vibrational excitations associated with such an interface by means of time-resolved, coherent phonon spectroscopy. GaP/Si(001) will serve as a model system. The polar semiconductor GaP and the non-polar semiconductor Si have similar lattice constants but different electronic and phononic properties. The main project aims are the experimental detection of interface-specific vibrational excitations and the correlation of their properties with the atomic structure of the interface. The latter will be modified and controlled by different parameters during the epitaxial growth and it will be structurally characterized with atomic resolution by scanning transmission electron spectroscopy. Coherent phonon spectroscopy is particularly well suited to investigate the dynamical coupling of electronic and phononic excitations. It is thus expected that the planned experiments will also provide interesting information about the dynamics of electronic excitations and charge transfer processes at buried, internal semiconductor interfaces.