National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, Tsukuba, 305-8568 Japan.
IMRA-JAPAN Material R &D Co. Ltd., 2-1 Asahi-machi, Kariya, Aichi 448-0032 Japan.
Sci Rep. 2023 Mar 23;13(1):4743. doi: 10.1038/s41598-023-31917-w.
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 Pb[Formula: see text]Sb[Formula: see text]O[Formula: see text] 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.
具有强几何各向异性的电子系统具有平带，其异常的能带色散有望诱导出各种各样的物理性质。然而，对于这些性质的出现，费米能级必须被钉扎在平带内。在这项研究中，我们对钙钛矿氧化物 Pb[Formula: see text]Sb[Formula: see text]O[Formula: see text]进行了第一性原理计算，从理论上阐明了自掺杂机制导致了该体系中费米能级在平带中的钉扎。因此，在费米能级处实现了非常高的态密度，并且通过平带机制，系统从铁磁态转变为基态，尽管系统中不包含任何磁性元素。这种化合物有可能成为在现实世界中展示平带系统性质的新平台。
