Light Scattering from Strongly Perturbed Semiconductors

本课题是基于布里渊散射探测界面弹性波的新技术，来测量数百千巴静水压力下固体的体弹性常数。这种独特的能力将允许研究立方体半导体中声子在压力下几乎普遍的软化及其在结构相变中的潜在作用。对半导体合金和异质结构的测量将允许隔离成分和界面应变效应。共振拉曼散射将用于研究钴基稀磁半导体中发现的交换介导声子重整化。另一个关于II-V型半导体的项目正试图阐明其外延生长过程中新颖有序的基本驱动机制，并探索通过应变稳定不稳定晶格的可能性。

This research project is developing a new technique, based on the detection of interface elastic waves by Brillouin scattering, to measure the bulk elastic constants of solids under hundreds of kilobars of hydrostatic pressure. This unique capability will permit the investigation of the almost universal softening of acoustic phonons with pressure in cubic semiconductors and their potential role in structural phase transitions. Measurements on semiconductor alloys and heterostructures will allow isolation of compositional and interfacial strain effects. Resonant Raman scattering will be employed to study the exchange-mediated phonon renormalization discovered in cobalt-based dilute magnetic semiconductors. Antoher program on II-V semiconductors is attempting to elucidate the fundamental driving mechanism for their novel ordering during epitaxial growth and to explore the possibility to stabilize through strain otherwise unstable crystal lattices.