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，这些化学键和电子态与材料的体相和表面的化学键和电子态截然不同。在这个项目的框架内，我们计划通过时间分辨的相干声子谱来研究与这种界面相关的振动激发动力学。GaP/Si（001）将作为模型系统。极性半导体GaP和非极性半导体Si具有相似的晶格常数，但具有不同的电子和声子性质。主要项目目标是实验检测特定界面的振动激发和它们的属性与界面的原子结构的相关性。后者将在外延生长过程中通过不同的参数进行修改和控制，并将通过扫描透射电子光谱仪进行原子分辨率的结构表征。相干声子谱特别适合于研究电子和声子激发的动力学耦合。因此，预计计划中的实验也将提供有趣的信息，在掩埋的内部半导体界面的电子激发和电荷转移过程的动态。

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.