在 Cu2OSeO3 中强 Dzyaloshinskii-Moriya 相互作用和铁电性的起源。

Strong Dzyaloshinskii-Moriya interaction and origin of ferroelectricity in Cu2OSeO3.

机构信息

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.

出版信息

Phys Rev Lett. 2012 Sep 7;109(10):107203. doi: 10.1103/PhysRevLett.109.107203.

DOI:10.1103/PhysRevLett.109.107203

PMID:23005322

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.

摘要

通过进行密度泛函计算，我们研究了 Cu2OSeO3 中 Skyrmion 态和铁电性的起源。我们发现，两种不同类型的 Cu 离子之间的 Dzyaloshinskii-Moriya 相互作用非常强，分别在没有和存在磁场的情况下诱导出螺旋基态和 Skyrmion 态。基于自旋有序诱导极化的一般模型，我们提出 Cu2OSeO3 在共线亚铁磁态的铁电极化来自于一种不寻常的机制，即由于自旋轨道耦合导致的单自旋位贡献。