  Spin-orbit coupling effects occurring in non-centrosymmetric materials are
known to be responsible for non-trivial spin configurations and a number of
emergent physical phenomena. Ferroelectric materials may be especially
interesting in this regard due to reversible spontaneous polarization making
possible for a non-volatile electrical control of the spin degrees of freedom.
Here, we explore a technologically relevant oxide material, HfO2, which has
been shown to exhibit robust ferroelectricity in a non-centrosymmetric
orthorhombic phase. Using theoretical modelling based on density-functional
theory, we investigate the spin-dependent electronic structure of the
ferroelectric HfO2 and demonstrate the appearance of chiral spin textures
driven by spin-orbit coupling. We analyze these spin configurations in terms of
the Rashba and Dresselhaus effects within the k.p Hamiltonian model and find
that the Rashba-type spin texture dominates around the valence band maximum,
while the Dresselhaus-type spin texture prevails around the conduction band
minimum. The latter is characterized by a very large Dresselhaus constant
{\alpha}D = 0.578 eV {\AA}, which allows using this material as a tunnel
barrier to produce tunneling anomalous and spin Hall effects that are
reversible by ferroelectric polarization.
