  In this work, we show that a gate electric field, applied in the base of the
field-effect devices, leads to inducing spin-orbit interactions (Rashba and
linear Dresselhauss) and confines the transport electrons in a two-dimensional
electron gas. On the basis of these phenomena we solve analytically the Pauli
equation when the Rashba strength and the linear Dresselhaus one are equal, for
a tuning value of the gate electric field $\mathcal{E}_g^*$. Using the transfer
matrix approach, we provide a joint description of the transport by varying the
bias electric field, $\mathcal{E}_b$. We can flip the spin of the incident
electrons, or block the spin-down completely. The robustness of this behavior
is proved when $\mathcal{E}_g^*$ changes by $\mathcal{E}_g^* \pm \delta
\mathcal{E}_g$.
