Spin current depolarization under high electric fields in undoped InGaAs

Carrier spin polarization in $In0.13Ga0.87As$ under high electric fields has been investigated. The spin polarization was created by optical spin orientation techniques and the inverse spin-Hall effect was employed to measure the spin polarization. For moderate electric fields, the spin polarization was constant, whereas the significant change in the spin polarization was found in the high electric field range. The spin-density rate equation, together with carrier transport analysis, clarifies that the observed change is attributed to the voltage-induced Auger process which modifies the carrier number in InGaAs.