First-principles calculation of the bulk magnetoelectric monopole density: Berry phase and Wannier function approaches

Article

关键词: CR2O3;    POLARIZATION;    CRYSTALS;   

DOI  :  10.1103/PhysRevB.93.195167

来源: SCIE

【 摘 要 】

We present a formalism to calculate the macroscopic magnetoelectric monopolization from first principles within the density-functional-theory framework. An expression for the monopolization in the case of insulating collinear magnetism is derived first in terms of spin-polarized Wannier functions, and then recast as a Berry phase. We propose an extension to the general, noncollinear case, which we implement computationally in the Wannier function form and use to calculate the magnetoelectric monopolization of LiMnPO4 and Cr2O3. We find that, while the former is well approximated by a summation over the formal local spin moments, the latter shows significant deviations from this approximation. We suggest that equating the Berry phase value with a sum over local moments provides an unambiguous route to defining the size of the local magnetic moment in magnetoelectric antiferromagnets containing only one type of magnetic ion.

【 授权许可】

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