Topological Phase Control by Molecular Chirality and Steric Anisotropy

Abstract

We develop a simple physical model using spheroidal molecules with chirality to control topological phases in a solid. Molecular rotation induces lattice distortion because of the anisotropy of intermolecular steric interaction, resulting in the emergence of the elastic field. We call this elastic field an emergent elastic field. We reveal that the emergent elastic field is a key to control helical and half-skyrmion structures. Utilizing the coupling between the emergent elastic fields and molecular orientations, we control topological phases by material parameters, temperature, and external perturbations. We also observe a novel re-entrant phase transition between the helical and thehalf-skyrmion phases.