Spin degree of freedom in ferromagnetic semiconductor heterostructures

Ferromagnetic III–V semiconductors, such as (Ga,Mn)As and (In,Mn)As, are among the promising materials in the field of semiconductor spintronics because of their good compatibility with the high quality III–V heterostructures. We show several examples of the novel spin-related properties of heterostructures containing a ferromagnetic component: (1) all-semiconductor (Ga,Mn)As/(Al,Ga)As/(Ga,Mn)As trilayers exhibiting spin-dependent scattering and tunneling magnetoresistance; (2) resonant tunneling structures with (Ga,Mn)As emitter, where spontaneous spin-splitting of the valence band is probed; (3) spin-light emitting diodes, in which spin-injection can be observed and (4) field effect transistor structures with a (In,Mn)As channel layer, making it possible to control the ferromagnetism by an electric field.