ABSTRACT

Controlling magnetic phenomena in semiconductors may allow new technological advances. In this chapter we review theoretical progress in understanding magnetism in silicon by doping transition metal elements. An in-depth study of single dopant energetics and bonding features at different sites is given. Spin-polarized densities of states, spin-polarized charge densities, and structural parameters are calculated and studied to yield a physical picture of the magnetic structure around transition metal dopants in Si. Next, other structures composed of many transition metal atoms in silicon, namely digital ferromagnetic heterostructures (DFHs) with and without defects, and trilayers, are studied to understand properties of extended transition metal structures. In particular, the conditions for half metallicity are described.