Elementary energy bands in crystalline solids
Department of Physics, Technion-Israel Institute
of Technology - Haifa 32000, Israel
Accepted: 21 March 2000
Elementary energy bands in solids are defined generalizing the notion of simple and composite energy bands. All energy branches of elementary energy bands are connected. Following the connectivity of the energy branches in elementary energy bands, a new notion of unavoidable degeneracy is established, for which the crossings can be moved but not removed. This degeneracy does not depend on the particular shape of the potential and is present in all crystals of some given space group symmetry.
PACS: 71.28.+d – Narrow-band systems; intermediate-valence solids / 02.20.Fh – Infinite groups / 02.40.Pc – General topology
© EDP Sciences, 2000