COEXISTENCE OF FERROMAGNETISM AND SUPERCONDUCTIVITY IN THE TWO-DIMENSIONAL FERROMAGNETIC t–J MODEL

The two-dimensional ferromagnetic t–J model is studied in the framework of slave-boson mean field theory. After solving the mean field self-consistent equations, we find that there exists a hole-doping region δ1<δ<δ2 in which p-wave superconductivity and ferromagnetism coexist. There also exists a T* line, under which pre-paired p-wave cooper pairs appear. The similarity and differences between our theoretical results and the experimental ones made for UGe2 are compared.