Far Infrared Magneto-Optical Absorption of Small Bismuth Particles.
Abstract
Small bismuth particles were used as a model system for a three dimensionally confined solid state plasma in an investigation of the change from semiclassical confinement to quantum confinement. Information on the carrier states was obtained from far infrared magneto-optical absorption measurements. The spectra were taken from 10 to 350 cm ^{-1} by Fourier transform spectroscopy with the samples typically immersed in liquid helium. Samples were pellets pressed from a mixture of bismuth particles and an insulating host with the volume fraction of bismuth less than 0.01. The particles were made by inert gas evaporation and characterized by transmission electron microscopy. Particles with diameters above 200nm show an abundance of field dependent resonances that can be successfully described by a semi-classical treatment for the solid state plasma using bulk bismuth parameters. As the mean particle diameter is reduced, the data show a dramatic qualitative change in resonance behavior. This change is thought to result from the appearance of discrete energy levels for the carriers when the plasma is quantum confined. The success of the model for large particles and the observed size dependence allow limits to be set on the size for which particles may be treated as small pieces of bulk crystal.
- Publication:
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Ph.D. Thesis
- Pub Date:
- 1991
- Bibcode:
- 1991PhDT.......258S
- Keywords:
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- Physics: Condensed Matter