  We predict it is possible to achieve high-efficiency room-temperature spin
injection from a mag- netic metal into InAs-based semiconductors using an
engineered Schottky barrier based on an InAs/AlSb superlattice. The Schottky
barrier with most metals is negative for InAs and positive for AlSb. For such
metals there exist InAs/AlSb superlattices with a conduction band edge
perfectly aligned with the metal's Fermi energy. The initial AlSb layer can be
grown to the thickness required to produce a desired interface resistance. We
show that the conductivity and spin lifetimes of such superlattices are
sufficiently high to permit efficient spin injection from ferromagnetic metals.
