Bansal Sakshi, Ali Asif, Reddy B H, Singh Ravi Shankar
Department of Physics, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462 066, India.
J Phys Condens Matter. 2021 Nov 2;34(4). doi: 10.1088/1361-648X/ac31fb.
We investigate the role of electron correlation in the electronic structure of honeycomb lattice LiRuOusing photoemission spectroscopy and band structure calculations. Monoclinic LiRuOhaving Ru network as honeycomb lattice undergoes magneto-structural transition at∼ 540 K from high temperature phase2/to low temperature dimerized phase2/. Room temperature valence band photoemission spectra reveal an insulating ground state with no intensity at Fermi level (). Ru 4band extracted from high and low photon energy valence band photoemission spectra reveal that the surface and bulk electronic structures are very similar in this system. Band structure calculations using generalized gradient approximation leads to metallic ground state while screened hybrid (YS-PBE0) functional reveals opening up of a gap in almost degenerate/orbitals, whereasorbital is already gapped. Ru 3core level spectra with prominent unscreened feature provides direct evidence of strong electron correlation among Ru 4electrons which is also manifested by |-|dependence of spectral density of states in the vicinity ofin the high-resolution spectra, establishing LiRuOas Mott insulator.
我们利用光电子能谱和能带结构计算研究了电子关联在蜂窝晶格LiRuO电子结构中的作用。具有Ru网络作为蜂窝晶格的单斜LiRuO在约540 K时从高温相2向低温二聚相2发生磁结构转变。室温价带光电子能谱显示出绝缘基态，费米能级（）处无强度。从高、低光子能量价带光电子能谱中提取的Ru 4能带表明，该系统中表面和体电子结构非常相似。使用广义梯度近似的能带结构计算导致金属基态，而筛选混合（YS-PBE0）泛函显示在几乎简并的/轨道中出现能隙，而轨道已经有能隙。具有突出未筛选特征的Ru 3芯能级光谱提供了Ru 4电子之间强电子关联的直接证据，这也由高分辨率光谱中在附近态密度的光谱密度的|-|依赖性表现出来，确立LiRuO为莫特绝缘体。
