Revealing hidden magneto-electric multipoles using Compton scattering

Abstract

Magneto-electric multipoles, which are odd under both space-inversion $\mathcal{I}$ and time-reversal $\mathcal{T}$ symmetries, are fundamental in understanding and characterizing magneto-electric materials. However, the detection of these magneto-electric multipoles is often not straightforward as they remain "hidden" in conventional experiments in part since many magneto-electrics exhibit combined $\mathcal{IT}$ symmetry. In the present work, we show that the anti-symmetric Compton profile is a unique signature for all the magneto-electric multipoles, since the asymmetric magnetization density of the magneto-electric multipoles couples to space via spin-orbit coupling, resulting in an anti-symmetric Compton profile. We develop the key physics of the anti-symmetric Compton scattering using symmetry analysis and demonstrate it using explicit first-principles calculations for two well-known representative materials with magneto-electric multipoles, insulating LiNiPO${}_4$ and metallic Mn${}_2$Au. Our work emphasizes the crucial roles of the orientation of the spin moments, the spin-orbit coupling, and the band structure in generating the anti-symmetric Compton profile in magneto-electric materials.

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Cited by in corpus (8)

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• Surface Magnetization in Antiferromagnets: Classification, example materials, and relation to magnetoelectric responses
• GdAlSi: An antiferromagnetic topological Weyl semimetal with non-relativistic spin splitting
• Kramers' degenerate magnetism and superconductivity
• Exploring energy landscapes of charge multipoles using constrained density functional theory
• Anti-symmetric Compton scattering in LiNiPO${}_4$: Towards a direct probe of the magneto-electric multipole moment