title: Femtosecond coherent control of spins in (Ga,Mn)As ferromagnetic semiconductors using light.
abstract: Using density matrix equations of motion, we predict a femtosecond collective spin tilt triggered by nonlinear, near-ultraviolet (approximately 3 eV), coherent photoexcitation of (Ga,Mn)As ferromagnetic semiconductors with linearly polarized light. This dynamics results from carrier coherences and nonthermal populations excited in the {111} equivalent directions of the Brillouin zone and triggers a subsequent uniform precession. We predict nonthermal magnetization control by tuning the laser frequency and polarization direction. Our mechanism explains recent ultrafast pump-probe experiments.
authors: Department of Physics, University of Crete, Heraklion, Crete 71003, Greece and Institute of Electronic Structure & Laser, Foundation for Research and Technology-Hellas, Heraklion, Crete 71110, Greece.
authors: M D
authors: MD
authors: Kapetanakis
authors: I E
authors: IE
authors: Perakis
authors: K J
authors: KJ
authors: Wickey
authors: C
authors: C
authors: Piermarocchi
authors: J
authors: J
authors: Wang