Perfect spin polarization in symmetric two-terminal mesoscopic rings

•Spin-polarized transport through a symmetric two-terminal mesoscopic ring studied.•Rashba and Dresselhaus spin–orbit interactions (RSOI and DSOI) considered.•We fixed Aharonov–Bohm (AB) magnetic flux penetrating the ring.•Nonzero and small difference between RSOI and DSOI leads to perfect spin filtering.•Mechanism of perfect spin filtering depends on AB magnetic flux.

Spin-polarized transport through an Aharonov–Bohm (AB) semiconductor mesoscopic ring is investigated in the presence of both the Rashba spin–orbit interaction (RSOI) and the Dresselhaus spin–orbit interaction (DSOI). The ring symmetrically bridges two input and output electrodes. Based on tight-binding model and Greenʼs function formalism, we find that for AB fluxes other than integer or half-integer multiples of the flux quanta the ring acts as a spin selective device with unit efficiency only when the difference between strengths of RSOI and DSOI is nonzero and small. Results of this study can be used to design a nonmagnetic-material-based perfect spin filter.