Tunnelling in k‐space application to degenerate valence bands

Abstract

AbstractHole tunnelling between light and heavy mass bands in a homogeneous semiconductor due to strong electric fields is analyzed in the framework of the spherical and degenerate at k = 0 bands with spin‐orbit interaction neglected. It is found that in k‐space intense transitions between bands occur in a ring‐shaped volume, whose symmetry axis is parallel to the electric field. At high fields, of the order of 30 kV/cm, the average diameter of the ring, where hole tunnelling is most intense, becomes smaller than the diameter of the optical phonon sphere. As a result, before the collision with an optical phonon, the ballistically moving hole experiences velocity modulation. Some possible experimental situations which would allow to discriminate the hole tunnelling in the degenerate bands from the collision dominated processes, are discussed briefly.