  The momentum-dependent Rashba and Dresselhaus spin-splitting has gained much
attention for its highly promising applications in spintronics. In the present
work, ab initio density functional theory calculations are performed to study
the spin-splitting effect in ferroelectric oxide perovskite KIO3. Our
calculations are additionally supported by symmetry adapted two-band k.p
Hamiltonian. Non-negligible spin-splitting effect is observed at conduction
band minimum (CBm) and valence band maximum (VBM) for rhombohedral R3m and R3c
phases. Linear Rashba terms successfully explain the splitting at VBM. However,
cubic terms become important in realizing spin-orientation near CBm. Our
results show the enhancement in Rashba parameters on tuning the ferroelectric
order parameter. Further, we have observed reversal of spin-orientation on
switching the direction of polarization.
