Exact Solutions of Domain Wall and Spiral Ground States in Hubbard Models

Abstract

We construct a set of exact ground states with a localized ferromagnetic domain wall and an extended spiral structure in a deformed flat-band Hubbard model. In the case of quarter filling, we show the uniqueness of the ground state with a fixed magnetization. We discuss a more realistic situation given by a band-bending perturbation, which can stabilize these curious structures. We study a conduction electron scattered by the domain wall and the spiral spins.