Flat band of kagome lattice in graphene plasmonic crystals

2021 ◽  
Author(s):  
Liqiang Zhuo ◽  
Huiru He ◽  
Ruimin Huang ◽  
Zhi Li ◽  
Weibin Qiu ◽  
...  
Keyword(s):  
Flat Band ◽  
Kagome Lattice ◽  
Plasmonic Crystals ◽  
Kagomé Lattice

scholarly journals Flat-Band-Enabled Triplet Excitonic Insulator in a Diatomic Kagome Lattice

2021 ◽  
Vol 126 (19) ◽  
Author(s):  
Gurjyot Sethi ◽  
Yinong Zhou ◽  
Linghan Zhu ◽  
Li Yang ◽  
Feng Liu
Keyword(s):  
Flat Band ◽  
Kagome Lattice ◽  
Kagomé Lattice ◽  
Excitonic Insulator

scholarly journals Kagome van-der-Waals Pd3P2S8 with flat band

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Seunghyun Park ◽  
Soonmin Kang ◽  
Haeri Kim ◽  
Ki Hoon Lee ◽  
Pilkwang Kim ◽  
...  
Keyword(s):  
Diamagnetic Susceptibility ◽  
Van Der Waals ◽  
Localized States ◽  
Flat Band ◽  
Two Dimensional ◽  
Kagome Lattice ◽  
Kagomé Lattice ◽  
Localized State ◽  
Low Dimensional ◽  
Important Structure

AbstractWith the advanced investigations into low-dimensional systems, it has become essential to find materials having interesting lattices that can be exfoliated down to monolayer. One particular important structure is a kagome lattice with its potentially diverse and vibrant physics. We report a van-der-Waals kagome lattice material, Pd3P2S8, with several unique properties such as an intriguing flat band. The flat band is shown to arise from a possible compact-localized state of all five 4d orbitals of Pd. The diamagnetic susceptibility is precisely measured to support the calculated susceptibility obtained from the band structure. We further demonstrate that Pd3P2S8 can be exfoliated down to monolayer, which ultimately will allow the possible control of the localized states in this two-dimensional kagome lattice using the electric field gating.

scholarly journals Interaction-Enhanced Group Velocity of Bosons in the Flat Band of an Optical Kagome Lattice

2020 ◽  
Vol 125 (13) ◽  
Author(s):  
Tsz-Him Leung ◽  
Malte N. Schwarz ◽  
Shao-Wen Chang ◽  
Charles D. Brown ◽  
Govind Unnikrishnan ◽  
...  
Keyword(s):  
Group Velocity ◽  
Flat Band ◽  
Kagome Lattice ◽  
Kagomé Lattice

scholarly journals Realization of flat band with possible nontrivial topology in electronic Kagome lattice

2018 ◽  
Vol 4 (11) ◽  
pp. eaau4511 ◽  
Author(s):  
Zhi Li ◽  
Jincheng Zhuang ◽  
Li Wang ◽  
Haifeng Feng ◽  
Qian Gao ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Edge State ◽  
Dimensional Structure ◽  
Flat Band ◽  
Destructive Interference ◽  
Two Dimensional ◽  
Kagome Lattice ◽  
Experimental Realization ◽  
Kagomé Lattice ◽  
Nontrivial Topology

The energy dispersion of fermions or bosons vanishes in momentum space if destructive quantum interference occurs in a frustrated Kagome lattice with only nearest-neighbor hopping. A discrete flat band (FB) without any dispersion is consequently formed, promising the emergence of fractional quantum Hall states at high temperatures. Here, we report the experimental realization of an FB with possible nontrivial topology in an electronic Kagome lattice on twisted multilayer silicene. Because of the unique low-buckled two-dimensional structure of silicene, a robust electronic Kagome lattice has been successfully induced by moiré patterns after twisting the silicene multilayers. The electrons are localized in the Kagome lattice because of quantum destructive interference, and thus, their kinetic energy is quenched, which gives rise to an FB peak in the density of states. A robust and pronounced one-dimensional edge state has been revealed at the Kagome edge, which resides at higher energy than the FB. Our observations of the FB and the exotic edge state in electronic Kagome lattice open up the possibility that fractional Chern insulators could be realized in two-dimensional materials.

scholarly journals Spin-polarized Dirac cone, flat band and saddle point in kagome magnet YMn6Sn6

2020 ◽  
Author(s):  
Man Li ◽  
Qi Wang ◽  
Guangwei Wang ◽  
Zhihong Yuan ◽  
Wenhua Song ◽  
...  
Keyword(s):  
Saddle Point ◽  
Hall Effect ◽  
Anomalous Hall Effect ◽  
Flat Band ◽  
Dirac Fermion ◽  
Kagome Lattice ◽  
Dirac Cone ◽  
Kagomé Lattice ◽  
Orbital Magnetism ◽  
Spin Polarized

Abstract Kagome-lattice of 3d-transition metals hosting Weyl/Dirac fermions and topological flat bands exhibit non-trivial topological characters and novel quantum phases, such as anomalous Hall effect and fractional quantum Hall effect. With consideration of spin-orbit coupling and electron correlation, several instabilities could be induced. The complete characters of the electronic structure of kagome lattice, i.e. the saddle point, Dirac-cone, and flat band, around the Fermi energy (EF) remain elusive in magnetic kagome materials. We present the first experimental observation of the complete features in ferromagnetic kagome layers of YMn6Sn6 helically coupled along the c-axis, by using angle-resolved photoemission spectroscopy and band structure calculations. We demonstrate a Dirac dispersion near EF arising from a spin-polarized orbital, which carries an intrinsic Berry curvature and contributes to the anomalous Hall effect in transport measurements. In addition, a flat band and a saddle point with a high density of states and with orbital-selective characters near EF are observed. These multi-orbital kagome features could cause multi-orbital magnetism. The Dirac fermion, flat band and saddle point in the vicinity of EF open an opportunity in manipulating the topological properties in magnetic materials.

scholarly journals Discrete flat-band solitons in the kagome lattice

2013 ◽  
Vol 87 (6) ◽  
Author(s):  
Rodrigo A. Vicencio ◽  
Magnus Johansson
Keyword(s):  
Flat Band ◽  
Kagome Lattice ◽  
Kagomé Lattice

scholarly journals Chern insulator with a nearly flat band in the metal-organic-framework-based Kagome lattice

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Santu Baidya ◽  
Seungjin Kang ◽  
Choong H. Kim ◽  
Jaejun Yu
Keyword(s):  
Density Functional ◽  
Metal Organic Framework ◽  
Chern Number ◽  
Flat Band ◽  
Kagome Lattice ◽  
Kagomé Lattice ◽  
Topological Quantum ◽  
Metal Organic ◽  
Fe Complexes ◽  
Carrier Doping

Abstract Based on first-principles density-functional theory (DFT) calculations, we report that the transition-metal bis-dithiolene, M3C12S12 (M = Mn and Fe), complexes can be a two-dimensional (2D) ferromagnetic insulator with nontrivial Chern number. Among various synthetic pathways leading to metal bis-dithiolenes, the simplest choice of ligand, Benzene-hexathiol, connecting metal cations to form a Kagome lattice is studied following the experimental report of time-reversal symmetric isostructural compound Ni3C12S12. We show sulfur and carbon-based ligands play the key role in making the complexes topologically nontrivial. An unusual topological quantum phase transition induced by the on-site Coulomb interaction brings a nearly flat band with a nonzero Chern number as the highest occupied band. With this analysis we explain the electronic structure of the class M3C12S12 and predict the existence of nearly flat band with nonzero Chern number and it can be a fractional Chern insulator candidate with carrier doping.

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