Coherent optical control of spin-spin interaction in doped semiconductors

C. PIERMAROCCHI; G. F. QUINTEIRO

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

APS

Año: 2004 vol. 70 p. 235210 - 235210

0163-1829

We provide a theory of laser-induced interaction between spins localized by impurity centers in a semiconductor host. By solving exactly the problem of two localized spins interacting with one itinerant exciton, ananalytical expression for the induced spin-spin interaction is given as a function of the spin separation, laser energy, and intensity. We apply the theory to shallow neutral donors (Si) and deep rare-earth magnetic impurities(Yb) in III-V semiconductors. When the photon energy approaches a resonance related to excitons bound to the impurities, the coupling between the localized spins increases, and may change from ferromagnetic to antiferromagnetic. This light-controlled spin interaction provides a mechanism for the quantum control of spins in semiconductors for quantum information processing; it suggests the realization of spin systems whose magnetic properties can be controlled by changing the strength and the sign of the spin-spin interaction.