Screening and exchange in the theory of the femtosecond kinetics of the electron-hole plasma

Abstract

This work deals with the dynamics of the nonthermalized electron-hole plasma in the subpicosecond regime. We computed different collision rates (electron-electron, electron-hole, electron-phonon) and discussed the relative efficiency of the different processes for the cases of static and dynamic screening of the interaction. We also considered how the inclusion of the exchange affected the screening amplitude and the collision rates. Calculations were bases upon GaAs. We conclude that dynamic screening is crucial for electrons in the conduction band at high plasma density [say, at densities above (1-2)x10 16 /cm 3 ] whereas it generally plays a minor role at low density and when describing hole dynamics. The excitation of heavy holes into the light-hole band by collisions with the conduction electrons is discussed in heavily p-doped GaAs.

Pauli blockade of the electron spin flip in bulk GaAs

“…where C and β are the scaling coefficient and scaling exponent respectively showing no dependence on k. Analogous scaling relations can be inferred from calculations on the electron-electron scattering rates including and excluding exchange 48 (see discussion below), and can also be deduced for the case of the correlation and exchange mean energies per electron in an electron-hole plasma in the context of a screened potential approximation. 49 We have fitted the experimental points shown in Fig.…”

“…This general argument has proved to be valid in calculations of carrier-carrier scattering by Collet in undoped GaAs in a static screening approximation. 48 From the results shown in Fig. 5 of Ref.…”

“…5 of Ref. 48 for the electron-electron scattering rates as a function of density, including and excluding the exchange interaction, a scaling relation between direct and exchange scattering rates analogous to Eq. (5) can be extracted.…”

Effect of the Pauli principle on photoelectron spin transport inp+GaAs

“…The effect of hole screening can be simply taken into account in the Random Phase Approximation (RPA) in the present case where the hole screening is dominant over the electronic one. In this case, the static Coulomb potential in Fourier space is given by [33,34] …”

Generalized Elliott-Yafet spin-relaxation time for arbitrary spin mixing

“…[17] We do not attempt a quantitative comparison with these experiments as in Ref. [18,19], because we would then also have to account for the dynamics of the optical excitation of electrons and both heavy and light holes [20,21], heavy-hole to light-hole scattering, and the interplay of electron-phonon and electron-electron Coulomb interactions [22,23], which makes a straightforward comparison with Yafet's formula difficult, if not impossible.…”