title: Sudden restoration of the band ordering associated with the ferromagnetic phase transition in a semiconductor.
abstract: The band ordering of semiconductors is an important factor in determining the mobility and coherence of the wave function of carriers, and is thus a key factor in device performance. However, in heavily doped semiconductors, the impurities substantially disturb the band ordering, leading to significant degradation in performance. Here, we present the unexpected finding that the band ordering is suddenly restored in Mn-doped GaAs ((Ga,Mn)As) when the Mn concentration slightly exceeds ∼0.7% despite the extremely high doping concentration; this phenomenon is very difficult to predict from the general behaviour of doped semiconductors. This phenomenon occurs with a ferromagnetic phase transition, which is considered to have a crucial role in generating a well-ordered band structure. Our findings offer possibilities for ultra-high-speed quantum-effect spin devices based on semiconductors.
authors.affiliation: Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Iriya
authors.initials: I
authors.lastname: Muneta
authors.affiliation: Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Ohya
authors.affiliation: Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Terada
authors.affiliation: Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Center for Spintronics Research Network, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tanaka