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BERNARDO SPAGNOLO

Doping dependence of spin lifetime of drifting electrons in GaAs bulks

  • Authors: Spezia, S; Persano Adorno, D; Pizzolato, N; Spagnolo, B
  • Publication year: 2010
  • Type: Altro
  • Key words: Spin polarized transport in semiconductors; spin relaxation and scattering; Monte Carlo simulation
  • OA Link: http://hdl.handle.net/10447/50705

Abstract

We study the effect of the impurity density on lifetimes and relaxation lengths of electron spins in the presence of a static electric field in a n-type GaAs bulk. The transport of electrons and the spin dynamics are simulated by using a semiclassical Monte Carlo approach, which takes into account the intravalley scattering mechanisms of warm electrons in the semiconductor material. Spin relaxation is considered through the D'yakonov-Perel mechanism, which is the dominant mechanism in III-V semiconductors. The evolution of spin polarization is analyzed by computing the lifetimes and depolarization lengths as a function of the doping density in the range 10^{13} - 10^{16} cm^{-3}, for different values of the amplitude of the static electric field (0.1 - 1.0 kV/cm). We find an increase of the electron spin lifetime as a function of the doping density, more evident for lattice temperatures lower than 150 K. Moreover, at very low intensities of the driving field, the spin depolarization length shows a nonmonotonic behaviour with the density. At the room temperature, the spin lifetimes and depolarization lengths are nearly independent on the doping density. The underlying physics is analyzed.