Electronic Band Structure

In solid-state physics, the electronic band structure (or simply band structure) of a solid describes those ranges of energy, called energy bands, that an electron within the solid may have ("allowed bands"), and ranges of energy called band gaps ("forbidden bands"), which it may not have. Band theory models the behavior of electrons in solids by postulating the existence of energy bands. It successfully uses a material's band structure to explain many physical properties of solids, such as electrical resistivity and optical absorption. Bands may also be viewed as the large-scale limit of molecular orbital theory. A solid creates a large number of closely spaced molecular orbitals, which appear as a band. Band structure derives from the dynamical theory of diffraction of the quantum mechanical electron waves in a periodic crystal lattice with a specific crystal system and Bravais lattice.