First principles study of the spontaneous electric polarization in Ga2−xFexO3Ga2−xFexO3

The spontaneous electric polarization (SEP) in the multiferroic Ga2−xFexO3Ga2−xFexO3 (x = 1/2, 1, 3/2) systems is determined from their electronic structure using a first principles method and the modern theory of polarization. This is done by following carefully the SEP on a path connecting the polar and centrosymmetric structures. For the antiferromagnetic GaFeO3 system, the SEP is found to be − 25.0 μC/cm2 which is 10 times larger than previous estimation given into the literature a few years ago. Similar SEP values are obtained for x = 1/2 and 3/2 where the system is highly magnetized. The homogeneous switching of this SEP through a centrosymmetric structure is discussed in terms of the total energy barrier and it is exhibited that such a process is particularly difficult to achieve in relation with the tetrahedral environment of half of the Ga atoms into the polar structure.

► The electric polarization is calculated from first principles method into GaFeO3 ► The concentration of Fe versus Ga is taken equal to 1/2, 1 and 3/2. ► The electric polarization is weakly affected when the Fe concentration is varied ► The energy barrier for homogeneous switching is found to be very high.