Conduction band

Position of the conduction band (orange) for different types of material;
VB = valence band, E _F = Fermi energy

The term conduction band belongs to the band model used to explain the electrical conductivity of materials. It denotes the energy band that lies at absolute temperature zero ( T = 0 K ) above the highest energy band occupied by electrons ( valence band ).

It can

partially overlap with the valence band (e.g. with sodium ) and thus be partially occupied (metals and semimetals )
separated from the valence band by the band gap and therefore unoccupied ( semiconductors and insulators ).

Importance in cargo transport

If electrons of a material are in the conduction band, they can easily absorb energy from an electric field due to free energy states in the conduction band . According to Bloch's theorem , comparable free particles , move as quasiparticles . The material is therefore electrically conductive.

In semiconductors and insulators, the conduction band is separated from the valence band by the band gap. Electrons can only overcome this through external energy input - through thermal , kinetic or photonic excitation (see also: photoelectric effect ).

The theoretical calculation of all bands of crystalline solids is done quantum mechanically using Bloch's theorem in order to obtain the electron states in the periodic potential (that of the atoms in the solid).

Individual evidence

^ ^A ^b Wolfgang Demtröder: Experimentalphysik. 3: Atoms, molecules and solids . 4th, revised edition. Springer Spectrum, Berlin Heidelberg 2010, ISBN 978-3-642-03911-9 , p. 469 .

[Demtröder_2010_469-1] A ^b Wolfgang Demtröder: Experimentalphysik. 3: Atoms, molecules and solids . 4th, revised edition. Springer Spectrum, Berlin Heidelberg 2010, ISBN 978-3-642-03911-9 , p. 469 .