On the possibility of using X‐ray Compton scattering to study magnetoelectrical properties of crystals. Issue 2 (16th February 2016)

• Record Type: Journal Article
• Authors: Collins, S. P.; Laundy, D.; Connolley, T.; van der Laan, G.; Fabrizi, F.; Janssen, O.; Cooper, M. J.; Ebert, H.; Mankovsky, S.
• Is Part Of: Acta crystallographica. Volume 72:Issue 2(2016:Mar.)
• Page Start: 197
• Page End: 205
• Publication Date: 2016-02-16
• Subjects: Compton scattering -- magnetoelectric properties -- synchrotron radiation -- density functional theory -- DFT -- Korringa–Kohn–Rostoker (KKR) Green's function method -- KKR method; Crystallography -- Periodicals; Condensed matter -- Periodicals; 548
• DOI: 10.1107/S2053273316000863
• Languages: English
• ISSNs: 2053-2733

Abstract

Abstract : The possibility of using X‐ray Compton scattering to reveal antisymmetric components of the electron momentum density, as a fingerprint of magnetoelectric sample properties, is investigated experimentally and theoretically by studying the polar ferromagnet GaFeO3 . Abstract : This paper discusses the possibility of using Compton scattering – an inelastic X‐ray scattering process that yields a projection of the electron momentum density – to probe magnetoelectrical properties. It is shown that an antisymmetric component of the momentum density is a unique fingerprint of such time‐ and parity‐odd physics. It is argued that polar ferromagnets are ideal candidates to demonstrate this phenomenon and the first experimental results are shown, on a single‐domain crystal of GaFeO3 . The measured antisymmetric Compton profile is very small (≃ 10 −5 of the symmetric part) and of the same order of magnitude as the statistical errors. Relativistic first‐principles simulations of the antisymmetric Compton profile are presented and it is shown that, while the effect is indeed predicted by theory, and scales with the size of the valence spin–orbit interaction, its magnitude is significantly overestimated. The paper outlines some important constraints on the properties of the antisymmetric Compton profile arising from the underlying crystallographic symmetry of the sample.