Femtosecond Demagnetization and Hot Hole Relaxation in Ferromagnetic GaMnAs

Abstract

We have studied ultrafast photoinduced demagnetization in GaMnAs via two-color time-resolved magneto-optical Kerr spectroscopy. Below-bandgap midinfrared pump pulses strongly excite the valence band, while near-infrared probe pulses reveal sub-picosecond demagnetization that is followed by an ultrafast ($\sim$1 ps) partial recovery of the Kerr signal. Through comparison with InMnAs, we attribute the signal recovery to an ultrafast energy relaxation of holes. We propose that the dynamical polarization of holes through $p$-$d$ scattering is the source of the observed probe signal. These results support the physical picture of femtosecond demagnetization proposed earlier for InMnAs, identifying the critical roles of both energy and spin relaxation of hot holes.

7 pages, 6 figures

References in corpus (5)

• Theory of ferromagnetic (III,Mn)V semiconductors
• Origin of the anomalous magnetic circular dichroism spectral shape in ferromagnetic (Ga,Mn)As: Impurity bands inside the band gap
• Ultrafast Enhancement of Ferromagnetism via Photoexcited Holes in GaMnAs
• Ultrafast demagnetization in the sp-d model: a theoretical study
• Multiple transfer of angular momentum quanta from a spin-polarized hole to magnetic ions in ZnMnSe/ZnBeSe quantum wells

Cited by in corpus (7)

• Coherent control of magnetization precession in ferromagnetic semiconductor (Ga,Mn)As
• Ultrafast Probes of Nonequilibrium Hole Spin Relaxation in Ferromagnetic Semiconductor GaMnAs
• Large Itinerant Electron Exchange Coupling in the Magnetic Topological Insulator MnBi2Te4
• Exchange scaling of ultrafast angular momentum transfer in 4$f$ antiferromagnets
• Manipulating Femtosecond Spin--Orbit Torques with Laser Pulse Sequences to Control Magnetic Memory States and Ringing
• Investigation of Magnetic Anisotropy and Heat Dissipation in Thin Films of Compensated Antiferromagnet CuMnAs by Pump-probe Experiment
• Nonlinear optics driven magnetism reorientation in semiconductors