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| Meta-magnetic semiconductors | ||||||||||||
Spintronics is currently one of the most exciting and rapidly developing areas of condensed matter physics, with the goal of harnessing both the spin and charge of carriers in electronic devices. Spintronic devices will combine the advantageous properties of magnetic and semiconductor materials, and are expected to be fast, non-volatile and versatile, capable of simultaneous data storage and processing, while at the same time consuming less energy. The ability to prepare and manipulate highly polarised carrier spin populations are fundamental requirements for spintronics and currently represent major challenges in this field. In this project, we shall investigate experimentally and theoretically a new family of magnetic semiconductor materials which offer the possibility to produce high degrees of spin polarisation at room temperature and which are also compatible with industrial semiconductor epitaxial growth and nano-technological processing techniques. We shall use magneto-optical spectroscopy to investigate a wide range of magneto-optical phenomena in epitaxial layers of binary and ternary alloy semiconductors incorporating high concentrations of transition metal ions, working towards the investigation of quantum heterostructures based on these materials. In particular, we shall study novel systems that combine “Kramer’s” and “non-Kramer’s” ions within one material, leading to a range of magnetic phases that are not obtainable in compound semiconductors when only one magnetic species is present. Photoluminescence and reflectivity spectroscopies will give insight into the excitonic states and shallow defect states within the materials; Raman spectroscopy will be used to probe the structural uniformity and strain in the epilayers. To support the experimental work, we shall use ab initio computational tools to investigate the lattice properties (lattice parameter, elastic constants) of these new materials, a knowledge of which is required to optimise the epitaxial growth process, and to model the phonon densities of states, in order to obtain a propoer interpretation of the Raman spectroscopy results. Finally, we shall investigate whether ab initio modelling can give insight into the types of magnetic order that these heterostructures exhibit and the influence of strain on the magnetic phase diagram. In addition, the student will be able to play a role in other ongoing projects in the optical spectroscopy of DMS heterostructures. The student will attend the Nanoscience Group meetings and will thereby gain an insight into all the Department’s activities in nanoscience research, as well as attending the Nanoscience Group’s postgraduate lecture series. Funding Notes Applicants should have a background in the physical sciences and have or expect to gain a First or Upper Second Class UK Honours degree, or the equivalent from an overseas University. Possible funding sources include the Doctoral Training Account (for UK applicants) or, for EU or exceptional overseas candidates, a University studentship. Contact Dr Daniel Wolverson (pysdw@bath.ac.uk) tel: +44 (0)1225 383321 for further information on the project, or see http://www.bath.ac.uk/grad-office/apply/ for details on how to apply. |
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