Chen Lei, Xie Fang, Sur Shouvik, Hu Haoyu, Paschen Silke, Cano Jennifer, Si Qimiao
Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX, 77005, USA.
Donostia International Physics Center, P. Manuel de Lardizabal 4, 20018, Donostia-San Sebastian, Spain.
Nat Commun. 2024 Jun 19;15(1):5242. doi: 10.1038/s41467-024-49306-w.
Flat electronic bands are expected to show proportionally enhanced electron correlations, which may generate a plethora of novel quantum phases and unusual low-energy excitations. They are increasingly being pursued in d-electron-based systems with crystalline lattices that feature destructive electronic interference, where they are often topological. Such flat bands, though, are generically located far away from the Fermi energy, which limits their capacity to partake in the low-energy physics. Here we show that electron correlations produce emergent flat bands that are pinned to the Fermi energy. We demonstrate this effect within a Hubbard model, in the regime described by Wannier orbitals where an effective Kondo description arises through orbital-selective Mott correlations. Moreover, the correlation effect cooperates with symmetry constraints to produce a topological Kondo semimetal. Our results motivate a novel design principle for Weyl Kondo semimetals in a new setting, viz. d-electron-based materials on suitable crystal lattices, and uncover interconnections among seemingly disparate systems that may inspire fresh understandings and realizations of correlated topological effects in quantum materials and beyond.
预计平带会呈现出成比例增强的电子关联，这可能会产生大量新颖的量子相和异常的低能激发。在具有晶体晶格且存在破坏性电子干涉（通常具有拓扑性）的基于d电子的系统中，人们对其的研究越来越多。然而，这种平带通常位于远离费米能的位置，这限制了它们参与低能物理过程的能力。在此，我们表明电子关联会产生钉扎在费米能上的新兴平带。我们在哈伯德模型中、在由万尼尔轨道描述的区域内证明了这一效应，在该区域中，通过轨道选择性莫特关联会出现有效的近藤描述。此外，关联效应与对称性约束共同作用，产生一种拓扑近藤半金属。我们的结果为新环境下的外尔近藤半金属提出了一种新颖的设计原则，即基于d电子的材料置于合适的晶体晶格上，并揭示了看似不同的系统之间的相互联系，这可能会激发对量子材料及其他领域中相关拓扑效应的新理解和实现。
