Magnetic and electronic spin dynamics in magnetic semiconductor quantum structures

Abstract

Diluted magnetic semiconductors offer a unique opportunity for studies which combine elements of semiconductor physics and magnetism, where one may exploit the strong spin exchange interaction between charge carriers and magnetic ions in the materials. Recent advances in the epitaxial growth of these systems have allowed the fabrication of new low dimension structures where either quantum wells or barriers contain magnetic species. Two experiments are described which demonstrate the utility of these systems for exploring novel physical phenomena. In the first, femtosecond spectroscopic measurements of optically-induced magnetization are performed on structures consisting of magnetic quantum wells confined by nonmagnetic barriers, where the formation and evolution of electron-based magnetic polarons in the wells is directly observed. In the second, double quantum well heterostructures having a thin magnetic barrier are studied by field-dependent photoluminescence measurements, revealing magnetically-tuneable barrier potentials and remarkably strong carrier polarizations.