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We provide a methodology to understand materials with complex bonding patterns, and apply it to the example of heteroanionic and lone pair materials. We build a tight-binding model based on Wannier functions fitted on density functional…

Materials Science · Physics 2024-10-28 Emily G. Ward , Alexandru B. Georgescu

This work presents a novel approach to describe spectral properties of graphene layers with well defined edges. We microscopically analyze the boundary problem for the continuous Bogoliubov-de Gennes-Dirac (BdGD) equations and derive the…

Mesoscale and Nanoscale Physics · Physics 2011-04-01 William J. Herrera , P. Burset , A. Levy Yeyati

We study how to construct Dirac fermion defined on the honeycomb lattice in position space. Starting from the nearest neighbor interaction in tight binding model, we show that the Hamiltonian is constructed by kinetic term and second…

High Energy Physics - Lattice · Physics 2014-09-04 Masaki Hirotsu , Tetsuya Onogi , Eigo Shintani

We revisit the localized Wannier state description of the twisted bilayer graphene, focusing on the chiral limit. We provide a simple method for constructing such 2D exponentially localized -- yet valley polarized -- Wannier states,…

Strongly Correlated Electrons · Physics 2021-09-02 Oskar Vafek , Jian Kang

Recently, topological Dirac-vortex modes in Kekul\'e-distorted photonic lattices have attracted broad interest and exhibited promising applications in robust photonic devices such as topological cavities, lasers, and fibers. However, due to…

The Seebeck coefficient is examined for two-dimensional Dirac electrons in the three-quarter filled organic conductor alpha-(BEDT-TTF)_2I_3 under hydrostatic pressure, where the Seebeck coefficient is proportional to the ratio of the…

Mesoscale and Nanoscale Physics · Physics 2024-04-10 Yoshikazu Suzumura , Takao Tsumuraya , Masao Ogata

Twisted moir\'e Dirac systems enable powerful miniband engineering but are largely fixed once the twist angle is set, whereas unidirectional (1D) electrostatic superlattices offer continuous control of Dirac anisotropy; yet robust…

Mesoscale and Nanoscale Physics · Physics 2026-03-03 Hanzhou Tan , Pilkyung Moon

Motivated by recent experiments on atomic Dirac fermions in a tunable honeycomb optical lattice, we study the attractive Hubbard model of superfluidity in the anisotropic honeycomb lattice. At weak-coupling, we find that the maximum mean…

Quantum Gases · Physics 2015-06-05 Shunji Tsuchiya , R. Ganesh , Arun Paramekanti

Recent advances in realizing artificial gauge fields on optical lattices promise experimental detection of topologically non-trivial energy spectra. Self-similar fractal energy structures generally known as Hofstadter butterflies depend…

Quantum Gases · Physics 2015-06-25 F. Yılmaz , F. Nur Ünal , M. Ö. Oktel

We recapitulate the principle enabling the phenomenon of dynamic localization, and provide model calculations for ultracold atoms in driven optical lattices which indicate that the localization effect remains almost unaffected by interband…

Quantum Gases · Physics 2015-03-19 Stephan Arlinghaus , Matthias Langemeyer , Martin Holthaus

We experimentally investigate a scheme for studying lattice transport phenomena, based on the controlled momentum-space dynamics of ultracold atomic matter waves. In the effective tight-binding models that can be simulated, we demonstrate…

Quantum Gases · Physics 2016-07-12 Eric J. Meier , Fangzhao Alex An , Bryce Gadway

A twist between two systems offers the possibility to drastically change the underlying physical properties. To that end, we study the bandstructure of twisted moir\'e potentials in detail. At sets of commensurate twisting angles, the low…

Quantum Gases · Physics 2025-04-11 Dean Johnstone , Shanya Mishra , Zhaoxuan Zhu , Laurent Sanchez-Palencia

We propose to realize Dirac states in an inclined two-dimensional Su-Schrieffer-Heeger model on a square lattice. We show that a pair of Dirac points protected by space-time inversion symmetry appear in the semimetal phase. The locations of…

Mesoscale and Nanoscale Physics · Physics 2022-06-07 Chang-An Li , Sang-Jun Choi , Song-Bo Zhang , Björn Trauzettel

We present a two-band model based on periodic H\"uckel theory, which is capable of predicting the existence and position of Dirac cones in the first Brillouin zone of an infinite class of two-dimensional periodic carbon networks, obtained…

Mesoscale and Nanoscale Physics · Physics 2014-06-24 Willem Van den Heuvel , Alessandro Soncini

Three-dimensional topological semimetals can support band crossings along one-dimensional curves in the momentum space (nodal lines or Dirac lines) protected by structural symmetries and topology. We consider rhombohedrally (ABC) stacked…

Mesoscale and Nanoscale Physics · Physics 2018-01-15 T. Hyart , R. Ojajärvi , T. T. Heikkilä

The band structures describing non-interacting particles in one-dimensional superlattices of arbitrary periodicity are obtained by an analytical diagonalization of the Hamiltonian without adopting the popular tight-binding approximation.…

Strongly Correlated Electrons · Physics 2013-06-18 Olaf Krüger , Alejandro Saenz

We report on a theoretical derivation of the electronic dielectric response of semiconductor nanocrystals using a tight-binding framework. Extending to the nanoscale the Hanke and Sham approach [Phys. Rev. B 12, 4501 (1975)] developed for…

Materials Science · Physics 2011-11-09 F. Trani , D. Ninno , G. Iadonisi

Using synthetic lattices of laser-coupled atomic momentum modes, we experimentally realize a recently proposed family of nearest-neighbor tight-binding models having quasiperiodic site energy modulation that host an exact mobility edge…

A Dirac comb of point measures in Euclidean space with bounded complex weights that is supported on a lattice inherits certain general properties from the lattice structure. In particular, its autocorrelation admits a factorization into a…

Metric Geometry · Mathematics 2007-05-23 Michael Baake

The Nielsen-Ninomiya theorem, dubbed `fermion-doubling', poses a problem for the naive discretization of a single (massless) Dirac cone on a two-dimensional surface. The inevitable appearance of an additional, unphysical fermionic mode can,…

Mesoscale and Nanoscale Physics · Physics 2023-06-21 Alexander Ziesen , Ion Cosma Fulga , Fabian Hassler