Flat band ferromagnetism in Pb2 Sb2O7 via a self-doped mechanism

Electron systems with strong geometrical frustrations have flat bands, and their unusual band dispersions are expected to induce a wide variety of physical properties. However, for the emergence of such properties, the Fermi level must be pinned within the flat band. In this study, we performed first-principles calculations on pyrochlore oxide Pb2Sb2O7 and theoretically clarified that the self-doping mechanism induces pinning of the Fermi level in the flat band in this system. Therefore, a very high density of states is realized at the Fermi level, and the ferromagnetic state transforms into the ground state via a flat band mechanism, although the system does not contain any magnetic elements. This compound has the potential to serve as a new platform for projecting the properties of flat band systems in the real world.

Automated summary

In this study, first-principles calculations were performed on the pyrochlore oxide Pb2Sb2O7, and it was theoretically clarified that the self-doping mechanism induces the pinning of the Fermi level within the flat band, resulting in a very high density of states and a transformation of the ferromagnetic state into the ground state via a flat band mechanism, despite the absence of magnetic elements in the system. This compound has the potential to serve as a new platform for projecting the properties of flat band systems in the real world.