Hase Izumi, Higashi Yoichi, Eisaki Hiroshi, Kawashima Kenji
National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, 1-1-1 Umezono, 305-8568, Tsukuba, Japan.
IMRA JAPAN Material R&D Co. Ltd, 2-1 Asahi-machi, 448-0032, Kariya, Aichi, Japan.
Sci Rep. 2024 Nov 3;14(1):26532. doi: 10.1038/s41598-024-77977-4.
Energy dispersion of electrons is the most fundamental property of the solid state physics. In models of electrons on a lattice with strong geometric frustration, the band dispersion of electrons can disappear due to the quantum destructive interference of the wavefunction. This is called a flat band, and it is known to be the stage for the emergence of various fascinating physical properties. It is a challenging task to realize this flat band in a real material. In this study, we performed first-principles calculations on two compounds, Pb As O and Pb Sn O , which are candidates to have flat bands near the Fermi level. Both compounds have electronic states close to flat bands, but the band width is significantly larger than that of Pb Sb O shown in previous research. Nevertheless, the density of states at the Fermi level of Pb As O is large enough to cause the system to undergo a ferromagnetic transition. In the case of Pb Sn O , pseudo-gap behavior near the Fermi level was observed. These findings underscore the importance of investigating the influence of flat bands on electronic energy dispersion, providing a crucial step toward understanding the emergence and characteristics of flat bands in novel materials.
电子的能量色散是固态物理学最基本的性质。在具有强烈几何阻挫的晶格上的电子模型中，由于波函数的量子相消干涉，电子的能带色散可能消失。这被称为平带，并且已知它是各种迷人物理性质出现的舞台。在真实材料中实现这种平带是一项具有挑战性的任务。在本研究中，我们对两种化合物Pb₅(AsO)₃和Pb₅(SnO)₃进行了第一性原理计算，它们是在费米能级附近可能具有平带的候选材料。两种化合物都具有接近平带的电子态，但带宽明显大于先前研究中所示的Pb₅(SbO)₃的带宽。然而，Pb₅(AsO)₃在费米能级处的态密度足够大，足以使系统发生铁磁转变。在Pb₅(SnO)₃的情况下，观察到费米能级附近的赝能隙行为。这些发现强调了研究平带对电子能量色散影响的重要性，为理解新型材料中平带的出现和特性迈出了关键一步。
