Diluted magnetic semiconductor superlattices

Abstract

Spin dependent device transport, where the distinction between spin up and spin down carriers arises from the presence of local diluted magnetic semiconductor (DMS) regions, offers the possibility of magnetic field control of transport. This paper describes through the use of numerical solutions to the spin dependent Wigner distribution function, the means by which dilute magnetic semiconductors layers can lead to a magnetic field dependent break in the symmetry of superlattice structures. Specific examples area given in which all of the barriers are composed of DMS layers, and as a function of magnetic field there is an alteration in the relative population of spin up and spin down carriers. The symmetry breaking structure consists of a superlattice with a single DMS layer. As a function of magnetic field the barrier is higher for one spin state and lower of the other leading to a local region of charge accumulation that is not present in periodic lattice. The application of this broken symmetry to the creation of nucleation sites for high field domains, and in some cases alter the properties of the propagating domain is discussed.