Nagaoka Ferromagnetism in Two-Band Hubbard Model

In the present paper, we investigate the existence of ferromagnetism in a two-band Hubbard model, by applying a recently-introduced method by us to study ferromagnetism in metallic clusters. We prove rigorously that the ground state of this model is ferromagnetic if the intra-orbital Coulomb repulsion between electrons is infinitely strong and only one hole exists in the system. Our theorem improves aprevious result. Furthermore, our method can also be applied to deal with the case of multiple holesNational Natural Science Foundation of China [11374017]SCI(E)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)ARTICLE2261-2706