  After decades of research, the low Curie temperature of ferromagnetic
semiconductors remains the key problem in the development of magnetic
semiconductor spintronic technologies. Removing this roadblock might require a
change of the field's basic materials paradigm by looking beyond ferromagnets.
Recent studies of relativistic magnetic and magnetotransport anisotropy
effects, which in principle are equally well present in materials with
ferromagnetically and antiferromagnetically ordered spins, have inspired our
search for antiferromagnetic semiconductors suitable for high-temperature
spintronics. Since these are not found among the magnetic counterparts of
common III-V or II-VI semi- conductors, we turn the attention in this paper to
high N \'eel temperature I-II-V magnetic compounds whose electronic structure
has not been previously identified. Our combined experimental and theoretical
work on LiMnAs provides basic prerequisite for the systematic research of this
class of materials by demonstrating the feasibility to grow single crystals of
group-I alkali metal compounds by molecular beam epitaxy, by demonstrating the
semiconducting band structure of the I-Mn-V's, and by analyzing their
spin-orbit coupling characteristics favorable for spintronics.
