All-Optical Control of Charge and Spin in GaAs: Densities and Currents

Stevens, Martin J.; Bhat, Ravi; Najmaie, Ali; Driel, H. M. van; Sipe, J. E.; Smirl, Arthur L.

doi:10.1007/978-3-662-09115-9_10

Cited by 4 publications

(1 citation statement)

References 62 publications

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“…, where the a and b subscripts denote the crystallographic axes. Equation 2.3 also can be written phenomenologically as (van Driel et al 1999;Stevens et al 2004;Najmaie et al 2003;Hache et al 1998)…”

Section: Introductionmentioning

confidence: 99%

All optical injection and detection of ballistic charge and spin currents in gallium arsinide, germanium, and silicon

Loren¹

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Section: Introductionmentioning

confidence: 99%

All optical injection and detection of ballistic charge and spin currents in gallium arsinide, germanium, and silicon

Loren¹

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Dynamics of charge currents ballistically injected in GaAs by quantum interference

Zhao

Loren

Smirl

et al. 2008

Journal of Applied Physics

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The dynamics of charge currents ballistically injected in GaAs bulk and quantum wells are spatially and temporally resolved. The electrons and holes are injected with oppositely directed velocities without the use of accelerating fields by quantum interference between two photon absorption of a 200fs, 1430nm fundamental pulse and one photon absorption of the corresponding second harmonic pulse. The subsequent charge motion is followed with ∼200fs temporal and ∼1nm spatial resolution by using tightly focused optical differential transmission techniques that are dependent on the relative phase of the incident pump pulses. Initially, the electrons and holes ballistically separate by up to ∼20nm, and a space charge field forms, which decelerates the carriers. Within this ∼1ps regime, the momentum relaxes by electron-hole and phonon scatterings, and the space charge field restores the electrons and holes to a common position; on time scales long compared to 1ps, ambipolar diffusion and recombination complete the return of the system to equilibrium. A rigid shift (damped simple harmonic oscillator) model for the electron motion reproduces the key features in the data, and the procedure for extracting the spatiotemporal dynamics of the electrons is shown to be immune to energy relaxation effects and forgiving of nonlinear saturation.

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Dynamics of optically injected two-dimensional currents

Sherman

Abrarov

Sipe

2008

Journal of Applied Physics

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We investigate the charge and spin dynamics of optically injected currents in multiple quantum well structures using a hydrodynamic model. The dynamics is very complex even on time scales of the order of 1 ps due to the interplay of Coulomb forces, electron-hole drag effects, and nonlinearity of the equations of motion. Our analysis is based on a numerical approach employing an expansion of the calculated quantities in a Hermite–Gaussian basis. We calculate the evolution of the density of injected carriers, analyze the pattern of charges after the injection, and extract the parameters that characterize the overall charge displacement in the optical pump-probe and terahertz radiation experiments. While these two parameters would take on the same value if the injected charge distributions moved rigidly, we find that their observed values should be different due to the complex behavior of the carrier motion. The spin flows arising from the spin-dependent skew scattering of electron by holes and corresponding spin density distributions are calculated and analyzed.

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All-Optical Control of Charge and Spin in GaAs: Densities and Currents

Cited by 4 publications

References 62 publications

All optical injection and detection of ballistic charge and spin currents in gallium arsinide, germanium, and silicon

All optical injection and detection of ballistic charge and spin currents in gallium arsinide, germanium, and silicon

Dynamics of charge currents ballistically injected in GaAs by quantum interference

Dynamics of optically injected two-dimensional currents

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