Objective
Semiconductor physics continues to present new challenges despite being a mature field. In particular, the combination of semiconductor physics with magnetic effects is one emerging and topical area, whilst epitaxial crystal growth techniques offer a degree of control over one, two or zero-dimensional carrier confinement which continues to provide new opportunities for basic research. The project will pursue some of the surprising effects observed in the magneto-optical spectroscopy of dilute magnetic semiconductors and has the overall aim of understanding better the spin structure of semiconductor energy bands under the effects of (i) low-dimensional carrier confinement, (ii) strong magnetic effects and (iii) high carrier concentrations.
Each of the separate topics (i-iii) has been a subject of recent activity in semiconductor physics and so, for example, much is known about the basic properties of carriers and excitons in low-dimensional systems. At high carrier densities, new quasi-particles (charged excitons) and collective excitations appear and this is still an active area of research. In parallel, much work has been done on low-dimensional magnetic semiconductors, especially two-dimensional quantum well (QW) structures containing manganese as the magnetic impurity. However, the detailed study of magnetic QW structures has recently revealed a surprising symmetry-breaking whose explanation will be investigated within this project, whilst some combinations of the topics (i-iii) have still received very little attention (for example, high carrier concentrations in magnetic nanostructures, magnetic structures of dimensionality less than two). These are areas addressed by the current project.
The work is not directly aimed at commercial exploitation. However, it is expected to have an impact on the emerging field of spintronics, where highly-doped magnetic semiconductors play a key role in one class of devices. Likewise, quantum dots are of interest in optoelectronics for novel semiconductor laser structures as well as in the ambitious area of single-electron devices. From a fundamental point of view, bringing together low-dimensionality and magnetism is of interest in view of the ability to manipulate the interaction between the spins of the band carriers and the magnetic impurity centres. Similarly, the symmetry-breaking in QWs whose study is one task of the project offers a new level of insight into basic spin processes in semiconductors.
Topic(s)
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BA2 7AY Bath
United Kingdom