Theory of Stark Effect in Crystals

Abstract

Abstract The change of the optical interband absorption of non‐conducting crystals in an external electric field is investigated. The degeneracy of the band structure is considered. The modification of the absorption by the electric field is shown to be the superposition of the Stark effect and of the Franz‐Keldysh effect. In particular, the transitions Γ → Γ and X 5 → X 5 in diamond type crystals are considered. The transition Γ → Γ shows a quadratic Stark effect and the transition X 5 → X 5 a linear one.