-------------------------------------------------------------------------------- ### Anti-symmetric Compton scattering in LiNiPO4: Towards a direct probe of the magneto-electric multipole moment -------------------------------------------------------------------------------- Sayantika Bhowal,Daniel O’Neill,Michael Fechner,Nicola A. Spaldin,Urs Staub,Jon Duffy, and Stephen P. Collins -------------------------------------------------------------------------------- #### Abstract: We present a combined theoretical and experimental investigation of the anti-symmetric Compton profile in LiNiPO$_4$ as a possible probe for magneto-electric toroidal moments. Understanding as well as detecting such magneto-electric multipoles is an active area of research in condensed matter physics. Our calculations, based on density functional theory, indicate an anti-symmetric Compton profile in the direction of the $t_y$ toroidal moment in momentum space, with the computed anti-symmetric profile around four orders of magnitude smaller than the total profile. The difference signal that we measure is consistent with the computed profile, but of the same order of magnitude as the statistical errors and systematic uncertainties of the experiment. Our results motivate further theoretical work to understand the factors that influence the size of the anti-symmetric Compton profile, and to identify materials exhibiting larger effects. -------------------------------------------------------------------------------- All calculations were performed using the Elk code (version:4.0.15). The main folder contains two separate folders corresponding to the two different k-mesh, used for the calculations of Compton profile in LiNiPO$_4$. Each folder contains input and the most relevant output files. The folder "3x6x6" contains the subfolder "fig3-data-files" that includes the data files corresponding to the theoretical plots, presented in the paper.