Femtosecond coherent control of spins in (Ga,Mn)As ferromagnetic semiconductors using light.
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.
Kapetanakis
M D
MD
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.
Perakis
I E
IE
Wickey
K J
KJ
Piermarocchi
C
C
Wang
J
J