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Proceedings Paper

Infrared cyclotron resonance of 'crossed' band gap superlattices at magnetic fields of upto 150T
Author(s): R. J. Nicholas
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Paper Abstract

Type II structures such as InAs/GaSb have the peculiar property that the valence band of theGaSb lies at a lower energy than the conduction band of the InAO). This crossed (or negative) bandgap configuration results in the intrinsic generation of high density gases of electrons and holes oneither side of the interface. In a superlattice, the formation of subbands due to wavefunction overlapallow the band gap overlap to be reduced, and ultimately made positive, by the reduction of theperiodicity(2). This transition from a semimetal to a semiconductor can also be generatedmagnetically(3). The action of a perpendicular magnetic field is to produce Landau levels which fanupwards in energy from the electrons and downwards in energy from the holes. If the superlattice hasa negative band gap at zero magnetic field, then the gap will decrease and then uncross as the magneticfield increases. For a superlattice whose band gap is Eg=-0.07eV, the lowest Landau levels have beencalculated to uncross at about 37T.

Paper Details

Date Published: 30 November 2017
PDF: 2 pages
Proc. SPIE 2104, 18th International Conference on Infrared and Millimeter Waves, 210492 (30 November 2017); doi: 10.1117/12.2298758
Show Author Affiliations
R. J. Nicholas, Clarendon Lab. (United Kingdom)

Published in SPIE Proceedings Vol. 2104:
18th International Conference on Infrared and Millimeter Waves
James R. Birch; Terence J. Parker, Editor(s)

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