Multipole antiferromagnets: New interlinked chapters in crystallography, band structure, and electronics (ChapterMP)


The aim of our materials research project is to experimentally establish interlinked new paradigms in crystallography, band structure, and electronics in multipole collinear antiferromagnets. Using diffraction and microscopy measurements up to the ultimate atomic resolution, we will demonstrate unique crystallography signatures of the multipole antiferromagnets which are beyond the established nomenclature of magnetic symmetry groups. They result in a fundamentally new form of a wavevector-dependent spin-splitting, which has been omitted in the band theory of solids, and which we will elucidate by spectroscopy measurements and ab initio calculations. We will demonstrate that these spin-split bands in the dipole-free antiferromagnets generate conserved highly-polarized spin currents, which are analogous to spin currents driving reading and writing functionalities in ferromagnetic memory devices. Beyond spin-electronics, we envisage impact of the project on fields ranging from macroscopic quantum and topological phases to dissipationless microelectronics.