Fig. 4: Theoretical investigation of pressure-induced magnetic transition.
From: Pressure-induced transition from a Mott insulator to a ferromagnetic Weyl metal in La2O3Fe2Se2

a magnetic phase transition of La2O3Fe2Se2 polycrystal within different Hubbard U values. b Exchange coupling parameters as a function of pressure within U = 2.1 eV. The inset illustrate three exchange interactions, including the nearest-neighbor interaction of Fe-Fe contribution (J1), the next-nearest-neighbor interaction of Fe-Se-Fe contribution (J2), and the next-nearest-neighbor interaction of Fe-O-Fe contribution (J2′).