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The Antisymmetric Gap and the Total Width of the Valence Band of Binary Compound Crystals
Author(s) -
Unger K.,
Neumann H.
Publication year - 1974
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.2220640115
Subject(s) - antisymmetric relation , band gap , chemistry , valence (chemistry) , valence band , binary number , fermi level , electronic band structure , condensed matter physics , quasi fermi level , semimetal , atomic physics , physics , quantum mechanics , mathematics , electron , arithmetic , organic chemistry , mathematical physics
Soft X‐ray emission, X‐ray photoemission, and ultraviolet photoemission measurements of binary compounds show an antisymmetric gap within the valence band. The ratio of this antisymmetric gap to the total width of the valence band is shown to be a simple function of the Phillips‐van Vechten ionicity parameter of the compound. This relation is valid as well for tetrahedrally as for octahedrally coordinated compounds and for such elemental compounds (Se, Te) which contain two kinds of bonds. The relation is useful to determine the ionicity parameter of a compound and to test empirical band structure calculations which are fitted t o optical transition energies. Furthermore, also a relation for the estimation of the total valence band width in terms of the Fermi energy and the Penn gap is given.