Understanding Anisotropic Exchange in Chiral Magnets

This lecture delves into the microscopic Hamiltonian of Cu₂OSeO3, focusing on the anisotropic exchange interaction to explain new phases. The instructor presents a REXS method to quantify the AEI constant and reveals the signature of this interaction. The lecture explores the surface spiral state, its appearance, and its properties, including its metastable nature and orientation dependence. Various scenarios of the new surface spiral state are discussed, shedding light on the interplay between anisotropies and modifications at the surface. Theoretical discussions on the topic are ongoing, aiming to understand the implications on skyrmions. The lecture also covers experimental setups and results from REXS experiments on Cu₂OSeO3 at different temperatures and magnetic fields.