valentiesbandmaxima

Valentiesbandmaxima is a term sometimes encountered in solid-state physics and materials science to describe the highest energy points of the valence band in a crystalline solid. In standard terminology these points are called the valence-band maximum (VBM). There can be more than one VBM located at different points in the Brillouin zone, depending on the material’s symmetry and electronic interactions.

Relation to band structure: The valence band consists of energy levels occupied by electrons at zero temperature. The energy difference between the VBM and the conduction-band minimum (CBM) defines the band gap. The k-point where the VBM is attained helps determine whether the gap is direct or indirect: if the CBM lies at the same k-point, the material has a direct gap; otherwise it is indirect. This distinction affects optical absorption and emission properties.

Measurement and calculation: The VBM can be determined experimentally by angle-resolved photoemission spectroscopy (ARPES) and related photoemission techniques. Theoretical estimates are obtained through electronic structure calculations such as density functional theory (DFT), often with many-body corrections (for example GW) to improve accuracy for band positions.

Materials and implications: In many conventional semiconductors the VBM is located at the Gamma point. For silicon, the VBM is at Gamma while the CBM lies near the X point, yielding an indirect gap. In direct-gap materials like GaAs, the VBM and CBM coincide at Gamma, enabling strong optical transitions.

Name usage: The term valentiesbandmaxima is not widely used in English-language literature; the standard term is valence-band maximum. The concept is the same, and discussions may refer to multiple VBMs across the Brillouin zone.