Doping Dependence of Spin Dynamics of Drifting Electrons in GaAs Bulks
S. Spezia, D. Persano Adorno, N. Pizzolato and B. Spagnolo
Dipartimento di Fisica e Tecnologie Relative, Group of Interdisciplinary Physics, Università di Palermo and CNISM, Viale delle Scienze, edificio 18, I-90128 Palermo, Italy
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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 an 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 lifetimes and depolarization lengths as a function of the doping density in the range 1013 ÷ 5 × 1016 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, spin lifetimes and depolarization lengths are nearly independent on the doping density. The underlying physics is analyzed.
DOI: 10.12693/APhysPolA.119.250
PACS numbers: 71.70.Ej, 72.25.Dc, 72.25.Rb