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Fundamental Zero Energy Gap States in Superlattices
Author(s) -
de Dios Leyva M.,
Alvarez R. P.,
Gondar J. L.
Publication year - 1984
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221250126
Subject(s) - superlattice , condensed matter physics , semiconductor , brillouin zone , band gap , quasi fermi level , direct and indirect band gaps , semimetal , discontinuity (linguistics) , valence (chemistry) , materials science , physics , optoelectronics , quantum mechanics , mathematics , mathematical analysis
The band structure of a model superlattice, in which the conduction band bottom in the first host semiconductor is located very close to or even below the valence band top in the other host semiconductor, is analyzed as a function of layer thickness and of the conduction band–valence band edge discontinuity. The analysis is carried out in the envelope‐function approximation and in Kane's two‐band framework. It is shown that with increasing magnitude of the discontinuity (or of layer thickness), the nature of the superlattice changes from a direct gap semiconductor to a direct zero gap semiconductor. Furthermore, it is also shown that in the direct zero energy gap states the valence and conduction bands may touch each other simultaneously over several circumferences in the Brillouin zone of the superlattice.