Plasmons and magnetoplasmons in semiconductor heterostructures

The purpose of this review is to survey the status of the theory and experiment which can contribute to our knowledge of plasmon excitations in synthetic semiconductor heterostructures. With increasing sophistication of experimental probes, plasmons are now often used as a diagnostic tool to characterize the electronic structure of new materials. The surface plasmon becoming known as plasmon–polariton is simply an electromagnetic (EM) wave that propagates along the interface separating the two media. The strength of the fields associated with the wave is localized at and decays exponentially away from the interface. In preparing this review we feel that, beyond the presentation of the results achieved, there is a need to examine carefully the methodologies employed to obtain such results. By methodologies, we do not mean to go into the details of the mathematical machinery (this is carefully avoided!). The time has come, however, to look with a critical eye at the development of the principles, tools, and applications of the model theories applied to diverse geometries of heterostructures. Attention is largely given to the non-radiative modes, scrutinizing the effects of an applied magnetic field, carrier collisions, retardation, and interaction with optical phonons. We have mostly confined our attention to the intrasubband modes, which could be investigated through the use of classical as well as quantal approaches. Abiding by the central theme of the review, numerous theoretical results on plasmons and magnetoplasmons in several geometries of practical interest have been gathered and reviewed. This survey is preceded by the basics of several methodologies, both classical and quantal, applicable to a wide variety of systems of varying interest. The report concludes addressing briefly the anticipated implications of plasmon observation in the respective composite systems under a variety of circumstances. Our satisfaction in writing this review, like any other review which covers a considerably longer period,was in bringing together the results of primary research papers and presenting some unified account of progress in the field. The background provided is believed to make less formidable the task of future writers of reviews in this field and hence enable them to deal more readily with particular aspects of the subjects, or with recent advances in those directions in which notable progress may have been made.