title: Bond distortion effects and electric orders in spiral multiferroic magnets.
abstract: In this paper we study the bond distortion effect on the electric polarization in spiral multiferroic magnets based on cluster and chain models. The bond distortion breaks the inversion symmetry and modifies the d-p hybridization. Consequently, it will affect the electric polarization, which can be divided into the spin-current part and the lattice-mediated part. The spin-current polarization can be written in terms of [Formula: see text] with anisotropic amplitude, and the lattice-mediated polarization exists only when the M-O-M bond is distorted. The electric polarization for three-atom M-O-M and four-atom M-O2-M clusters is calculated. We also study possible electric ordering in three kinds of chains made of different clusters. We apply our theory to multiferroic cuprates and find that the results are qualitatively in agreement with experimental observations.
authors.affiliation: Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China. hbchen@zju.edu.cn
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Chen
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.forename: You-Quan
authors.initials: YQ
authors.lastname: Li