Mean-field analysis of ground state in multiferroic RFeO (R: rare earths)

Yoshii, Kenji  ; Nomura, Takuji*; Ikeda, Naoshi*

The rare-earth iron system RFeO shows ferroelectricity due to charge ordering of iron ions below 330 K. Also, the iron spins shows ferrimagnetism below 250 K and thus becomes multiferroic. Although this system was discovered almost a decade ago, its detailed properties remain unclear. In this study, we have calculated its ground state based on mean-field approximation. Various charge-ordered states have been observed. However, a ferroelectric state was not most stable. This suggests that the ferroelectricity is governed by the other factors such as lattice distortion.