ABSTRACT
This chapter discusses a possible new methodology in semiconductor nano-spintronics to realize a design-based new class of nano-spintronics with high Curie temperature: high-density nano-spintronics devices caused by spinodal nano-decomposition, high-speed-switching spintronics devices, and energy-saving spin-based devices. It also discusses the electronic structure and ferromagnetic mechanism in III-V and II-VI-based dilute magnetic semiconductors, spinodal nano-decomposition, and blocking phenomena in the semiconductor nanomagnet based on the local density approximation. In the delta doping, dopant atoms are confined to a single atomic plane within a semiconductor and are concentrated on one or two atomic layers in a crystal plane. The doping problem also appears in the valence control of wide band-gap semiconductors. In addition to incorporating transition metals into various semiconductors to realize ferromagnetic dilute magnetic semiconductors for spintronics devices, recently a novel class of magnetic materials incorporating non-transitionmetal atoms with/without lattice defects has attracted great attention among both theoretical and experimental scientists.
