Systematic study of polarized electron emission from strained GaAs∕GaAsP superlattice photocathodes

Abstract

Spin-polarized electron photoemission has been studied for GaAs∕GaAs1−xPx strained superlattice cathodes grown by gas-source molecular beam epitaxy. The superlattice structural parameters are systematically varied to optimize the photoemission characteristics. The heavy-hole and light-hole transitions are reproducibly observed in quantum efficiency spectra, enabling direct measurement of the band energies and the energy splitting. Electron-spin polarization as high as 86% with over 1% quantum efficiency has been observed.

Measurement Of Neutron Radius In Lead By Parity Violating Scattering Flash ADC DAQ

“…This negative electron affinity makes it possible to emit the spin polarized electrons from the conduction band. The difference between bulk GaAs crystal and supperlattice GaAs crystal is given in [47] and the exact details of super-lattice GaAs cathode used in Jefferson lab can be found here [48]. A schematic diagram of strained GaAs crystal and super-lattice strained GaAS crystal is shown in figure 2.7.…”

Study of the ¹²C(e, e2p) Reaction in a Correlations Dominant Regime with Q² = 2.0 (GeV/c)² and XB > 1

“…The electrons used are produced at the injector by photo-emission from a gallium arsenide (GaAs) superlattice photocathode by illuminating it with laser-light of 780 nm wavelength from a titanium-sapphire laser [34]. The superlattice consists of thin layers of GaAs which have a lattice mismatch, inducing strain in the structure.…”

Polarization Possibilities of Small Spin-Orbit Interaction in Strained-Superlattice Photocathodes

“…A recent systematic study shows, however, that the peak polarization seems saturated even though the heavy-hole (HH) and light-hole (LH) band splitting is increased significantly, indicating that there is a material specific spin relaxation mechanism [1]. It is widely accepted that the D'yakonov-Perel mechanism is the dominant spin relaxation mechanism in the III-V compound superlattice structures with a low p-doping (≤ 10 17 cm -3 ), and that the spin relaxation may be reduced by choosing a material with a smaller spin-orbit interaction.…”