English
Related papers

Related papers: Flat bands in fractal-like geometry

200 papers

Dispersionless flat bands can be classified into two types: (1) non-singular flat bands whose eigenmodes are completely characterized by compact localized states; and (2) singular flat bands that have a discontinuity in their Bloch…

Applied Physics · Physics 2023-08-01 Pragalv Karki , Jayson Paulose

We address the problem of analytically extracting a countable infinity of flat, non-dispersive bands in a periodic array of cells that comprise branching Vicsek geometries of higher and higher generations. Through a geometric construction,…

Mesoscale and Nanoscale Physics · Physics 2022-11-15 Sougata Biswas , Amrita Mukherjee , Arunava Chakrabarti

Flat bands imply lack of itinerancy due to some constraints that, in principle, results in anomalous behaviors with randomness. By a molecular orbital (MO) representation of the flat band systems, random MO models are introduced where the…

Disordered Systems and Neural Networks · Physics 2022-01-05 Yasuhiro Hatsugai

We study the formation and properties of perfectly-flat zero energy bands in a multi-layer graphene systems in the chiral limit. Employing the degrees of freedoms of the multi-layer system, such as relative twist-angle and relative shifts,…

Mesoscale and Nanoscale Physics · Physics 2024-04-25 Roi Makov , Francisco Guinea , Ady Stern

The existence of flat bands is generally thought to be physically possible only for dimensions larger than one. However, by exciting a system with different orthogonal states this condition can be reformulated. In this work, we demonstrate…

Optics · Physics 2019-07-10 Gabriel Cáceres-Aravena , Rodrigo A. Vicencio

\textit{Holey Graphene} (HG) is a widely used graphene material for the synthesis of high-purity and highly crystalline materials. In this work, we explore the electronic properties of a periodic distribution of lattice holes, demonstrating…

Mesoscale and Nanoscale Physics · Physics 2024-04-09 Abdiel de Jesús Espinosa-Champo , Gerardo G. Naumis

Flat bands with small energy dispersion can give rise to strongly correlated electronic and topological phases, especially when located at the Fermi level. Whilst flat bands have been experimentally realized in two-dimensional (2D) twisted…

The interplay of topological characteristics in real space and reciprocal space can lead to the emergence of unconventional topological phases. In this Letter, we implement a novel mechanism for generating higher-Chern flat bands on the…

Strongly Correlated Electrons · Physics 2021-11-23 Yifei Guan , Oleg V. Yazyev , Alexander Kruchkov

We study non-Hermitian photonic lattices that exhibit competition between conservative and non-Hermitian (gain/loss) couplings. A bipartite sublattice symmetry enforces the existence of non-Hermitian flat bands, which are typically embedded…

Optics · Physics 2017-08-30 Daniel Leykam , Sergej Flach , Y. D. Chong

Though several theoretical models have been proposed to design electronic flat-bands, the definite experimental realization in two-dimensional atomic crystal is still lacking. Here we propose a novel and realistic flat-band model based on…

Materials Science · Physics 2021-02-04 Jiang Zeng , Ming Lu , Haiwen Liu , Hua Jiang , X. C. Xie

Two-dimensional atomic crystals can radically change their properties in response to external influences such as substrate orientation or strain, resulting in essentially new materials in terms of the electronic structure. A striking…

Flatbands play an important role in correlated quantum matter and have novel applications in photonic lattices. Synthetic magnetic fields and destructive interference in lattices are traditionally used to obtain flatbands. However, such…

We investigate the spectral properties of a quasi-one-dimensional lattice in two possible dimerisation configurations. Both configurations are characterized by the same lattice topology and the identical spectra containing a flat band at…

Mesoscale and Nanoscale Physics · Physics 2017-09-19 D. Bercioux , O. Dutta , E. Rico

The bands of graphite are extremely sensitive to topological defects which modify the electronic structure. In this paper we found non-dispersive flat bands no farther than 10 meV of the Fermi energy in slightly twisted bilayer graphene as…

Mesoscale and Nanoscale Physics · Physics 2010-12-21 E. Suárez Morell , J. D. Correa , P. Vargas , M. Pacheco , Z. Barticevic

Certain lattice wave systems in translationally invariant settings have one or more spectral bands that are strictly flat or independent of momentum in the tight binding approximation, arising from either internal symmetries or fine-tuned…

Mesoscale and Nanoscale Physics · Physics 2018-06-07 Daniel Leykam , Alexei Andreanov , Sergej Flach

We construct a simple model for electrons in a three-dimensional crystal where a combination of short-range hopping and spin-orbit coupling results in nearly flat bands characterized by a non-trivial Z2 topological index. The flat band is…

Mesoscale and Nanoscale Physics · Physics 2012-01-27 C. Weeks , M. Franz

Motivated by the recent theoretical studies on a two-dimensional (2D) chiral Hamiltonian based on the Su-Schrieffer-Heeger chains, we experimentally and computationally demonstrate that topological flat frequency bands can occur at open…

Mesoscale and Nanoscale Physics · Physics 2020-11-25 Kai Qian , Linghua Zhu , Keun Hyuk Ahn , Camelia Prodan

We have studied how a generic bilayer kagome lattice behave upon layer rotation. We employed a Tight Binding model with one orbital per site and found (i) for low rotational angles, and at low energies, the same flat bands structure like in…

Mesoscale and Nanoscale Physics · Physics 2019-10-28 F. Crasto de Lima , R. H. Miwa , E. Suárez Morell

We study flat bands of periodic graphs in a Euclidean space. These are infinitely degenerate eigenvalues of the corresponding adjacency matrix, with eigenvectors of compact support. We provide some optimal recipes to generate desired bands,…

Mathematical Physics · Physics 2023-04-28 Mostafa Sabri , Pierre Youssef

Materials science and the study of the electronic properties of solids are a major field of interest in both physics and engineering. The starting point for all such calculations is single-electron, or non-interacting, band structure…

Quantum Physics · Physics 2020-01-08 Alicia J. Kollár , Mattias Fitzpatrick , Peter Sarnak , Andrew A. Houck