Kook Tae Kim,  Margaret R. McCarter, Vladimir A. Stoica,  Sujit Das,  Christoph Klewe,

Elizabeth P. Donoway, David M. Burn, Padraic Shafer,  Fanny Rodolakis, Mauro A. P. Gonçalves,

Fernando Gómez-Ortiz,  Jorge Íñiguez,  Pablo García-Fernández,  Javier Junquera,  Sandhya Susarla,

Stephen W. Lovesey,  Gerrit van der Laan,  Se Young Park,  Lane W. Martin,  John W. Freeland,

Ramamoorthy Ramesh & Dong Ryeol Lee

Abstract

Resonant elastic X-ray scattering (REXS) offers a unique tool to investigate solid-state systems providing spatial knowledge from diffraction combined with electronic information through the enhanced absorption process, allowing the probing of magnetic, charge, spin, and orbital degrees of spatial order together with electronic structure. A new promising application of REXS is to elucidate the chiral structure of electrical polarization emergent in a ferroelectric oxide superlattice in which the polarization vectors in the REXS amplitude are implicitly described through an anisotropic tensor corresponding to the quadrupole moment.
Here, we present a detailed theoretical framework and analysis to quantitatively analyze the experimental results of Ti L-edge REXS of a polar vortex array formed in a PbTiO3/SrTiO3 superlattice. Based on this theoretical framework, REXS for polar chiral structures can become a useful tool similar to x-ray resonant magnetic scattering (XRMS), enabling a comprehensive study of both electric and magnetic REXS on the chiral structures.

https://www.nature.com/articles/s41467-022-29359-5