title: Electrical spin injection from an n-type ferromagnetic semiconductor into a III-V device heterostructure.
abstract: The use of carrier spin in semiconductors is a promising route towards new device functionality and performance. Ferromagnetic semiconductors (FMSs) are promising materials in this effort. An n-type FMS that can be epitaxially grown on a common device substrate is especially attractive. Here, we report electrical injection of spin-polarized electrons from an n-type FMS, CdCr(2)Se(4), into an AlGaAs/GaAs-based light-emitting diode structure. An analysis of the electroluminescence polarization based on quantum selection rules provides a direct measure of the sign and magnitude of the injected electron spin polarization. The sign reflects minority rather than majority spin injection, consistent with our density-functional-theory calculations of the CdCr(2)Se(4) conduction-band edge. This approach confirms the exchange-split band structure and spin-polarized carrier population of an FMS, and demonstrates a litmus test for these FMS hallmarks that discriminates against spurious contributions from magnetic precipitates.
authors.affiliation: Materials Science and Technology Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA.
authors.forename: George
authors.initials: G
authors.lastname: Kioseoglou
authors.forename: Aubrey T
authors.initials: AT
authors.lastname: Hanbicki
authors.forename: James M
authors.initials: JM
authors.lastname: Sullivan
authors.forename: Olaf M J
authors.initials: OM
authors.lastname: van 't Erve
authors.forename: Connie H
authors.initials: CH
authors.lastname: Li
authors.forename: Steven C
authors.initials: SC
authors.lastname: Erwin
authors.forename: Robert
authors.initials: R
authors.lastname: Mallory
authors.forename: Mesut
authors.initials: M
authors.lastname: Yasar
authors.forename: Athos
authors.initials: A
authors.lastname: Petrou
authors.forename: Berend T
authors.initials: BT
authors.lastname: Jonker
mesh_terms: D005290:Ferric Compounds; D008280:Magnetics; D012666:Semiconductors
chemical_list: D005290:Ferric Compounds