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In iron-based superconductors, band inversion of $d$- and $p$-orbitals yields Dirac semimetallic states. We theoretically investigate their topological properties in normal and superconducting phases, based on the tight-binding model…

Superconductivity · Physics 2019-09-18 Takuto Kawakami , Masatoshi Sato

We report on Bloch-Zener oscillations of an ultracold Fermi gas in a tunable honeycomb lattice. The quasi-momentum distribution of the atoms is measured after sequentially passing through two Dirac points. We observe a double-peak feature…

We study the spectrum of the 1D Dirac Hamiltonian encompassing the bound and scattering states of a fermion distorted by a static background built from $\delta$-function potentials. We distinguish between "mass-spike" and "electrostatic"…

Mathematical Physics · Physics 2020-10-22 J. Mateos Guilarte , Jose M. Munoz-Castaneda , Irina Pirozhenko , Lucia Santamaria-Sanz

Moir\'e superlattices formed in two-dimensional semiconductor heterobilayers provide a new realization of Hubbard model physics in which the number of electrons per effective atom can be tuned at will. We report on an exact diagonalization…

Strongly Correlated Electrons · Physics 2021-08-10 Nicolás Morales-Durán , Pawel Potasz , Allan H. MacDonald

Inspired by recent advances in the manipulation of atoms trapped near 1D waveguides and pro- posals to use surface acoustic waves on piezoelectric substrates for the same purpose, we show the potential of two-dimensional platforms. We…

Quantum Physics · Physics 2018-07-04 F. Galve , R. Zambrini

We show that the evolution of two-component particles governed by a two-dimensional spin-orbit lattice Hamiltonian can reveal transitions between topological phases. A kink in the mean width of the particle distribution signals the closing…

Quantum Gases · Physics 2017-11-16 Wei-Wei Zhang , Barry C. Sanders , Simon Apers , Sandeep K. Goyal , David L. Feder

We study the two-dimensional Dirac operator with an arbitrary combination of electrostatic and Lorentz scalar $\delta$-interactions of constant strengths supported on a smooth closed curve. For any combination of the coupling constants a…

Analysis of PDEs · Mathematics 2020-07-21 Jussi Behrndt , Markus Holzmann , Thomas Ourmières-Bonafos , Konstantin Pankrashkin

The three-dimensional Dirac semimetal is distinct from its two-dimensional counterpart due to its dimensionality and symmetry. Here, we observe that molecule-based quasi-two-dimensional Dirac fermion system, $\alpha$-(BEDT-TTF)$_2$I$_3$,…

Strongly Correlated Electrons · Physics 2023-11-23 Naoya Tajima , Yoshitaka Kawasugi , Takao Morinari , Ryuhei Oka , Toshio Naito , Reizo Kato

Photoinduced topological phase transitions in the Dirac-electron systems have attracted intensive research interest since its theoretical prediction in graphene, where the application of circularly polarized light opens a gap at the Dirac…

Strongly Correlated Electrons · Physics 2022-09-27 Keisuke Kitayama , Masao Ogata , Masahito Mochizuki , Yasuhiro Tanaka

We demonstrate how to control the spectra and current flow of Dirac electrons in both a graphene sheet and a topological insulator by applying either two linearly polarized laser fields with frequencies $\omega$ and $2\omega$ or a…

Mesoscale and Nanoscale Physics · Physics 2015-06-18 Pablo Rodriguez-Lopez , Joseph J. Betouras , Sergey E. Savel'ev

Quadratic band touching (QBT) points are widely observed in 2D and 3D materials, including bilayer graphene and Luttinger semimetals, and attract significant attention from theory to experiment. However, even in its simplest form, the 2D…

Strongly Correlated Electrons · Physics 2024-02-29 Hongyu Lu , Kai Sun , Zi Yang Meng , Bin-Bin Chen

We explore a two-dimensional Hubbard model adapted to host altermagnetic states. Utilizing Hartree-Fock (HF) and dynamical mean field theory (DMFT), we uncover that the magnetic solutions of this model feature Dirac points in their…

Strongly Correlated Electrons · Physics 2025-05-30 Lorenzo Del Re

In a recent experiment on the interlayer magnetoresistance in the quasi-two-dimensional organic salt, $\alpha$-(BEDT-TTF)$_2$I$_3$, it has been observed that at low temperatures, interlayer tunneling attains phase coherence, leading to the…

Strongly Correlated Electrons · Physics 2023-11-21 Yuki Nakamura , Takao Morinari

Holographic quantum matter exploits the AdS/CFT correspondence to study systems in condensed matter physics. An example of these systems are strongly correlated semimetals, which feature a rich phase diagram structure. In this work, we…

High Energy Physics - Theory · Physics 2024-06-04 Sebastián Bahamondes , Ignacio Salazar Landea , Rodrigo Soto-Garrido

In this paper the phase diagram of Dirac semimetals is studied within lattice Monte-Carlo simulation. In particular, we concentrate on the dynamical chiral symmetry breaking which results in semimetal/insulator transition. Using numerical…

Strongly Correlated Electrons · Physics 2016-12-07 V. V. Braguta , M. I. Katsnelson , A. Yu. Kotov , A. A. Nikolaev

We reported about observation of Dirac points in a helically structured 1D photonic crystals, moreover, both as in the presence of longitudinal magnetic field as its absence. We obtained analytical formulas for Dirac points frequencies and…

Optics · Physics 2021-11-16 A. H. Gevorgyan

We consider the fate of the Wigner crystal state in a two dimensional system of massive Dirac electrons as the effective fine structure constant $\alpha$ is increased. In a Dirac system, larger $\alpha$ naively corresponds to stronger…

Strongly Correlated Electrons · Physics 2022-07-06 Sandeep Joy , Brian Skinner

We report infrared magneto-spectroscopy studies on thin crystals of an emerging Dirac material ZrTe5 near the intrinsic limit. The observed structure of the Landau level transitions and zero-field infrared absorption indicate a…

Materials Science · Physics 2017-07-12 Y. Jiang , Z. L. Dun , H. D. Zhou , Z. Lu , K. -W. Chen , S. Moon , T. Besara , T. M. Siegrist , R. E. Baumbach , D. Smirnov , Z. Jiang

This is a short review of two-dimensional Dirac fermions in graphene and similar systems such as boron nitride, quasi-2D organic salts $\alpha$-(BEDT-TTF)$_2$I$_3$, artificial graphene with cold atoms in optical lattices, etc. The emphasis…

Mesoscale and Nanoscale Physics · Physics 2013-06-04 Jean-Noel Fuchs

Topological semimetals, such as Dirac, Weyl, or line-node semimetals, are gapless states of matter characterized by their nodal band structures and surface states. In this work, we consider layered (topologically trivial) insulating systems…

Mesoscale and Nanoscale Physics · Physics 2022-05-12 Saavanth Velury , Taylor L. Hughes