title: Strong Dzyaloshinskii-Moriya interaction and origin of ferroelectricity in Cu2OSeO3.
abstract: By performing density functional calculations, we investigate the origin of the Skyrmion state and ferroelectricity in Cu2OSeO3. We find that the Dzyaloshinskii-Moriya interactions between the two different kinds of Cu ions are extremely strong and induce the helical ground state and the Skyrmion state in the absence and presence of a magnetic field, respectively. On the basis of the general model for the spin-order induced polarization, we propose that the ferroelectric polarization of Cu2OSeO3 in the collinear ferrimagnetic state arises from an unusual mechanism, i.e., the single-spin-site contribution due to the spin-orbit coupling.
authors.affiliation: Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, People's Republic of China.
authors.forename: J H
authors.initials: JH
authors.lastname: Yang
authors.forename: Z L
authors.initials: ZL
authors.lastname: Li
authors.forename: X Z
authors.initials: XZ
authors.lastname: Lu
authors.forename: M-H
authors.initials: MH
authors.lastname: Whangbo
authors.forename: Su-Huai
authors.initials: SH
authors.lastname: Wei
authors.forename: X G
authors.initials: XG
authors.lastname: Gong
authors.forename: H J
authors.initials: HJ
authors.lastname: Xiang