  Nonlinear spintronics, which combines nonlinear dynamics and spintronics,
opens a new route for controlling spins and spin dynamics beyond conventional
spintronics based on linear responses. Strongly correlated electron systems,
which can have large nonlinear responses, are promising candidates for
nonlinear spintronics. In this paper, we focus on the nonlinear Edelstein
effect (NEE), a generalization of the Edelstein effect, and study the impact of
electron correlations on the NEE by performing numerical calculations on a
Hubbard model. We find that correlation effects can either enhance or suppress
the nonlinear response. We show that the enhancement and suppression of the
response are due to the real and imaginary components of the self-energy,
respectively. Additionally, we have explored the relationship between the NEE
and photomagnetic or optomagnetic effects. Our findings demonstrate that
electron correlations can either enhance or suppress the optical spin
injection, depending on the light frequency, while always strengthening the
inverse Faraday effect.
