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oh_ Band theory

oh_ iohABand theoryjAIqzAqzAdqqwpLq_AA dqGlM[A(dq)g Band theory (BANDORI argument, Band theory), the periodic atomic arrangement, with a molecular substance, is one of the theories described by the quantum mechanics of electrons in the crystal state in particular, typically, in the crystal electron energy , the (electronic) wavenumber $\ textbf (K)$ W\ Function representing the relationship $\ epsilon = \ epsilon (\ textbf (K))$ vZ@SwB Point to a general method of calculation.

oh_AAwGlM[gW In the band theory, the relationship between energy and wavenumber $\ epsilon = \ epsilon (\ textbf (K))$ iUWjxAGlM[ohi oh\ jB (Dispersion relation), the energy band (band structure) is called.

ubzAdqg (dqdq )A gqwB According to the theorem of Bloch, the electronic wave function in the crystal (electronic states of electrons in crystals), which is designated by the number of quantum called the wavenumber. AGlM[gWIB This may have been written to ensure that the principleSERU an expression of energy and frequency.

A\ieAGlM[ohMbvi ohMbv jB The effects of crystal structure according to the translational symmetry, between the energy band gap (band gap) can cause.

AEoh\P} Metal, Schematic diagram simple in structure band of insulator and semiconductor

GlM[ohdq`A tF~MbvA GlM[ohtF~B In semiconductors and insulators the energy band is divided into zones conduction and valence band, place semi-Lumi Fellows will present in the gap in the metal crosses the Fermi surface is at least one energy band. tAGlM[ohAB Conversely, some features of this energy band can be classified as metallic and insulating materials.

A`20ImB These metals, the picture of the classification of the insulator 20 in the middle of the century had been established. Poh_i bg jA dqnB The simple band theory can not explain, however, isolated state (Mott insulator) and there have also been research in the field called strongly correlated electron systems.