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We theoretically study intrinsic superconductivity in doped Dirac semimetals. Dirac semimetals host bulk Dirac points, which are formed by doubly degenerate bands, so the Hamiltonian is described by a $4 \times 4$ matrix and six types of…

Superconductivity · Physics 2016-07-19 Tatsuki Hashimoto , Shingo Kobayashi , Yukio Tanaka , Masatoshi Sato

We have studied the evolution of the topological properties of a band-engineered AB-stacked bilayer honeycomb structure in the presence of a Haldane flux. Without a Haldane flux, band engineering makes the band touching points (the…

Mesoscale and Nanoscale Physics · Physics 2023-08-09 Sayan Mondal , Saurabh Basu

A Dirac point in the Hermitian photonic system will split into a pair of exceptional points (EPs) or even spawn a ring of EPs if non-Hermiticity is involved. Here, we present a new type of non-Hermitian Dirac point which is situated in the…

Optics · Physics 2024-04-29 Jun Wang , Jie Liu , Peng Hu , Qiao Jiang , Dezhuan Han

Non-Hermitian systems, which contain gain or loss, commonly host exceptional point degeneracies rather than the diabolic points found in Hermitian systems. We present a class of non-Hermitian lattice models with symmetry-stabilized diabolic…

Mesoscale and Nanoscale Physics · Physics 2020-06-17 Haoran Xue , Qiang Wang , Baile Zhang , Y. D. Chong

A key problem in the field of quantum criticality is to understand the nature of quantum phase transitions in systems of interacting itinerant fermions, motivated by experiments on a variety of strongly correlated materials. Much attention…

Strongly Correlated Electrons · Physics 2021-06-30 Rufus Boyack , Hennadii Yerzhakov , Joseph Maciejko

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

Two-dimensional (2D) coupled resonant optical waveguide (CROW), exhibiting topological edge states, provides an efficient platform for designing integrated topological photonic devices. In this paper, we propose an experimentally feasible…

We investigate the effects of a perpendicular electric field applied to multilayer phosphorene nanoribbons with zigzag and armchair edges. Within the context of the tight-binding model, we explore the electronic properties of these systems…

Mesoscale and Nanoscale Physics · Physics 2019-09-04 J. D. S. Forte , D. J. P. de Sousa , J. Milton Pereira

This review aims at a theoretical discussion of Dirac points in two-dimensional systems. Whereas Dirac points and Dirac fermions are prominent low-energy electrons in graphene (two-dimensional graphite), research on Dirac fermions in…

Mesoscale and Nanoscale Physics · Physics 2014-10-16 Mark O. Goerbig , Gilles Montambaux

Two-dimensional lattices of coupled micropillars etched in a planar semiconductor microcavity offer a workbench to engineer the band structure of polaritons. We report experimental studies of honeycomb lattices where the polariton…

We study spontaneous symmetry breaking in a system of spinless fermions in the Honeycomb lattice paying special emphasis to the role of an enlarged unit cell on time reversal symmetry broken phases. We use a tight binding model with nearest…

Strongly Correlated Electrons · Physics 2013-03-14 Adolfo G. Grushin , Eduardo V. Castro , Alberto Cortijo , Fernando de Juan , Maria A. H. Vozmediano , Belen Valenzuela

The recent discovery of higher-order topology has largely enriched the classification of topological materials. Theoretical and experimental studies have unveiled various higher-order topological insulators that exhibit topologically…

Mesoscale and Nanoscale Physics · Physics 2022-05-04 Zihao Wang , Dongjue Liu , Hau Tian Teo , Qiang Wang , Haoran Xue , Baile Zhang

Ultracold fermions trapped in a honeycomb optical lattice constitute a versatile setup to experimentally realize the Haldane model [Phys. Rev. Lett. 61, 2015 (1988)]. In this system, a non-uniform synthetic magnetic flux can be engineered…

Quantum Gases · Physics 2013-01-15 N. Goldman , E. Anisimovas , F. Gerbier , P. Ohberg , I. B. Spielman , G. Juzeliunas

We propose helical topological superconductivity away from the Fermi surface in three-dimensional time-reversal-symmetric odd-parity multiband superconductors. In these systems, pairing between electrons originating from different bands is…

Mesoscale and Nanoscale Physics · Physics 2024-07-01 Masoud Bahari , Song-Bo Zhang , Chang-An Li , Sang-Jun Choi , Philipp Rüßmann , Carsten Timm , Björn Trauzettel

We study the one-band Hubbard model on the honeycomb lattice using a combination of quantum Monte Carlo (QMC) simulations and static as well as dynamical mean-field theory (DMFT). This model is known to show a quantum phase transition…

Strongly Correlated Electrons · Physics 2020-03-09 Marcin Raczkowski , Robert Peters , Th\d{i} Thu Phùng , Nayuta Takemori , Fakher F. Assaad , Andreas Honecker , Javad Vahedi

We investigate the phase diagram of spinless fermions with nearest and next-nearest neighbour density-density interactions on the honeycomb lattice at half-filling. Using Exact Diagonalization techniques of the full Hamiltonian and…

Strongly Correlated Electrons · Physics 2015-08-28 Sylvain Capponi , Andreas M. Läuchli

Dirac materials are of great interest as condensed matter realizations of the Dirac and Weyl equations. In particular, they serve as a starting point for the study of topological phases. This physics has been extensively studied in…

Mesoscale and Nanoscale Physics · Physics 2020-08-11 P. Sathish Kumar , Igor F. Herbut , R. Ganesh

We theoretically investigate the emergence of non-hermitian physics at the heterojunction of a type-II Dirac semi-metal (DSM) and a dirty superconductor (DSC). The non-hermiticity is introduced in the DSM through the self-energy term…

Mesoscale and Nanoscale Physics · Physics 2021-07-07 Sayan Jana , Debashree Chowdhury , Arijit Saha

We analyze the magneto-optical conductivity (and related magnitudes like transmittance and Faraday rotation of the irradiated polarized light) of some elemental two-dimensional Dirac materials of group IV (graphene analogues, buckled…

Mesoscale and Nanoscale Physics · Physics 2024-03-20 M. Calixto , A. Mayorgas , N. A. Cordero , E. Romera , O. Castaños

Recently, there has been a lot of activity in the research field of topological non-Hermitian physics, partly driven by fundamental interests and partly driven by applications in photonics. However, despite these activities, a general…

Mesoscale and Nanoscale Physics · Physics 2019-06-26 W. B. Rui , Y. X. Zhao , Andreas P. Schnyder