Intervalley scattering in GaAs: ab initio calculation of the effective parameters for Monte Carlo simulations |
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Authors: | J Sjakste V Tyuterev N Vast |
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Institution: | (1) Laboratoire des Solides Irradiés, CEA/DSM-CNRS-Ecole Polytechnique, 91128 Palaiseau, France |
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Abstract: | Interactions between excited electrons and short-wavelength (intervalley) phonons in GaAs are studied using density functional
theory for the conduction bands, and density functional perturbation theory for phonon frequencies and matrix elements of
the electron–phonon interaction. We have calculated the deformation potentials (DPs) and the average intervalley scattering
time 〈τ〉. The integration of the scattering probabilities over all possible final states in the Brillouin zone has been performed
without any ad hoc assumption about the behavior of the electron–phonon matrix elements nor the topology of the conduction
band. For transitions from the L point to Γ valley (within the first conduction band), we find 〈τ〉L to be 1.5 ps at 300 K, in good agreement with time-resolved photoluminescence experiment. We discuss the difference between
our calculated DPs, and effective parameters used in Monte Carlo simulations of optical and transport properties of semiconductors.
The latter are based on Conwell’s model, in which electron–phonon interaction is described by one single constant and a parabolic
model is used for conduction bands. We deduce the effective DP from our 〈τ〉, and compare it to our calculated DPs. We conclude
that only effective DPs obtained from a full calculation of 〈τ〉 are relevant parameters for Monte Carlo simulations.
PACS 71.10-w; 72.10.Di; 71.55.Eq |
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