Significant effect of carrier concentration on spin lifetime at low temperatures in strained Si0.1Ge0.9

Using lateral spin transport measurements, we experimentally estimate the spin diffusion length (λ) and spin lifetime (τ) in strained n-Si
0.1
Ge
0.9
with two-different carrier concentrations (n) of ~1×10
¹⁸
cm
^-3
and ~5×10
¹⁸
cm
^-3
in the temperature range from 8 K to room temperature. We find a marked difference in τ depending on n at temperatures less than 100 K. We propose that, in the degenerate regime, the intravalley spin-flip scattering mechanism should be considered in the strained n-Si
0.1
Ge
0.9
.