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Motivated by the study of flat bands in models of twisted bilayer graphene (TBG), we give abstract conditions which guarantee the existence of a discrete set of parameters for which periodic Hamiltonians exhibit flat bands. As an…

Analysis of PDEs · Mathematics 2023-09-12 Jeffrey Galkowski , Maciej Zworski

We present a scheme to controllably improve the accuracy of tight-binding Hamiltonian matrices derived by projecting the solutions of plane-wave ab initio calculations on atomic orbital basis sets. By systematically increasing the…

A general framework for the kinetic modelling of non-relativistic polyatomic gases is proposed,where each particle is characterized both by its velocity and by its internal state, and the Boltzmann collisionoperator involves suitably…

Mathematical Physics · Physics 2023-01-05 Thomas Borsoni , Marzia Bisi , Maria Groppi

An accurate description of the low-energy electronic bands in twisted bilayer graphene (tBLG) is of great interest due to their relation to correlated electron phases, such as superconductivity and Mott-insulator behavior at half-filling.…

Mesoscale and Nanoscale Physics · Physics 2024-04-17 Daniel Bennett , Daniel T. Larson , Louis Sharma , Stephen Carr , Efthimios Kaxiras

We consider the mapping of tight-binding electronic structure theory to a local spin Hamiltonian, based on the adiabatic approximation for spin degrees of freedom in itinerant-electron systems. Local spin Hamiltonians are introduced in…

A procedure to obtain single-electron wavefunctions within the tight-binding formalism is proposed. It is based on linear combinations of Slater-type orbitals whose screening coefficients are extracted from the optical matrix elements of…

Materials Science · Physics 2016-09-16 R. Benchamekh , F. Raouafi , J. Even , F. Ben Cheikh Larbi , P. Voisin , J. -M. Jancu

An electrodynamic response of graphene to a strong electromagnetic radiation is considered. A hot electron model (HEM) is introduced and a corresponding system of nonlinear equations is formulated. Solutions of this system are found and…

Mesoscale and Nanoscale Physics · Physics 2019-09-18 S. A. Mikhailov

By taking into account the possibility of all the intralayer as well as the interlayer current orderings, we derive an eight-band model for interacting electrons in bilayer graphene. With the numerical solution to the model, we show that…

Strongly Correlated Electrons · Physics 2015-08-31 Xin-Zhong Yan , C. S. Ting

Parametric gates and processes engineered from the perspective of the static effective Hamiltonian of a driven system are central to quantum technology. However, the perturbative expansions used to derive static effective models may not be…

We analyze a description of twisted graphene bilayers, that incorporates deformation of the layers due to the nature modern interlayer potentials, and a modification of the hopping parameters between layers in the light of the classic…

Strongly Correlated Electrons · Physics 2019-05-29 Francisco Guinea , Niels R. Walet

It is shown that at low densities, quantum dots with few electrons may be mapped onto effective charge-spin models for the low-energy eigenstates. This is justified by defining a lattice model based on a many-electron pocket-state basis in…

Condensed Matter · Physics 2009-10-28 John H. Jefferson , Wolfgang Häusler

In this study we consider the Hamiltonian approach for the construction of a map for a system with nonlinear resonant interaction, including phase trapping and phase bunching effects. We derive basic equations for a single resonant…

Correlated insulators and superconductivity have been observed in "magic-angle" twisted bilayer graphene, when the nearly flat bands close to neutrality are partially filled. While a momentum-space continuum model accurately describes these…

Strongly Correlated Electrons · Physics 2019-06-04 Hoi Chun Po , Liujun Zou , T. Senthil , Ashvin Vishwanath

The exploration of quantum phenomena in complex materials such as moir\'e superlattices is limited by the O(N^3) scaling of conventional electronic structure methods. Here we introduce a high-performance tight-binding framework that reduces…

Computational Physics · Physics 2026-01-21 Zichong Zhang , Shuze Zhu

We consider multileg ladders of Rydberg atoms which have been proposed as quantum simulators for the compact Abelian Higgs model (CAHM) in 1+1 dimensions [Y. Meurice, Phys. Rev. D 104, 094513 (2021)] and modified versions of theses…

Quantum Physics · Physics 2024-12-02 Jin Zhang , Shan-Wen Tsai , Yannick Meurice

We demonstrate that there exists a continuum Hamiltonian $H(\bf{r},\bf{p})$ that is formally the operator equivalent of the general tight-binding method, inheriting the associativity and Hermiticity of the latter operator. This provides a…

Materials Science · Physics 2019-01-16 F. Rost , R. Gupta , M. Fleischmann , D. Weckbecker , N. Ray , J. Olivares , M. Vogl , S. Sharma , O. Pankratov , S. Shallcross

We present a linear response calculation for twisted bilayer graphene. The calculation is performed for both the continuum and tight-binding models, with the aim of assessing the validity of the former. All qualitatively important features…

Mesoscale and Nanoscale Physics · Physics 2018-11-21 T. Stauber , T. Low , G. Gómez-Santos

We show how to include the Jahn-Teller coupling of \mo phonons to the electrons in the continuum model formalism which describes small-angle twisted bilayer graphene. These phonons, which strongly couple to the valley degree of freedom, are…

Superconductivity · Physics 2020-07-03 M. Angeli , M. Fabrizio

Opening, in a controllable way, the energy gap in the electronic spectrum of graphene is necessary for many potential applications, including an efficient carbon-based transistor. We have shown that this can be achieved by chemical…

Materials Science · Physics 2008-09-05 D. W. Boukhvalov , M. I. Katsnelson

We discuss the effect of elastic deformations on the electronic properties of bilayer graphene membranes. Distortions of the lattice translate into fictitious gauge fields in the electronic Dirac Hamiltonian which are explicitly derived…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Eros Mariani , Alexander J. Pearce , Felix von Oppen
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