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The search for symmetry-protected 2D Dirac semimetals analogous to graphene is important both for fundamental and practical interest. The 2D Dirac cones are protected by crystalline symmetries and magnetic ordering may destroy their…

Mesoscale and Nanoscale Physics · Physics 2017-03-23 Jing Wang

We propose a new concept of two-dimensional (2D) Dirac semiconductor which is characterized by the emergence of fourfold degenerate band crossings near the band edge and provide a generic approach to realize this novel semiconductor in the…

Materials Science · Physics 2022-02-02 Botao Fu , Chao He , Da-Shuai Ma , Zhi-Ming Yu , Yong-Hong Zhao , Yugui Yao

We investigate the emergence of extra Dirac points in the electronic structure of a periodically spaced barrier system, i.e., a superlattice, on single-layer graphene, using a Dirac-type Hamiltonian. Using square barriers allows us to find…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 M. Barbier , P. Vasilopoulos , F. M. Peeters

A ballistic strip of graphene (width W>> length L) connecting two normal metal contacts is known to have a minimum conductivity of 4e^{2}/pi h at the Dirac point of charge neutrality. We calculate what happens if one of the two contacts…

Mesoscale and Nanoscale Physics · Physics 2013-07-09 A. R. Akhmerov , C. W. J. Beenakker

Half a century ago, Veselago proposed left-handed materials with negative permittivity and permeability, in which waves propagate with phase and group velocities in opposite directions. Significant work has been undertaken to attain this…

Mesoscale and Nanoscale Physics · Physics 2016-09-27 Gil-Ho Lee , Geon-Hyoung Park , Hu-Jong Lee

We reexamine the electronic structure of graphene on SiC substrate by angle-resolved photoemission spectroscopy. We directly observed multiply cloning of Dirac cone, in addition to ones previously attributed to reconstruction. The…

Materials Science · Physics 2022-03-21 C. L. Wu , Q. Wan , C. Peng , S. K. Mo , R. Z. Li , K. M. Zhao , Y. P. Guo , C. D. Zhang , N. Xu

The mode-dependent transmission of relativistic ballistic massless Dirac fermion through a graphene based double barrier structure is being investigated for various barrier parameters. We compare our results with already published work and…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Ahmed Jellal , El Bouazzaoui Choubabi , Hocine Bahlouli , Abdullah Aljaafari

In this work we present an optical lattice setup to realize a full Dirac Hamiltonian in 2+1 dimensions. We show how all possible external potentials coupled to the Dirac field can arise from perturbations of the existing couplings of the…

The extraordinary electronic properties of Dirac materials, the two-dimensional partners of Weyl semimetals, arise from the linear crossings in their band structure. When the dispersion around the Dirac points is tilted, the emergence of…

Mesoscale and Nanoscale Physics · Physics 2019-07-31 M. Milićević , G. Montambaux , T. Ozawa , I. Sagnes , A. Lemaître , L. Le Gratiet , A. Harouri , J. Bloch , A. Amo

We study structural and electronic properties of graphene grown on SiC substrate using scanning tunneling microscope (STM), spot-profile-analysis low energy electron diffraction (SPA-LEED) and angle resolved photoemission spectroscopy…

Mesoscale and Nanoscale Physics · Physics 2017-07-19 Lunan Huang , Yun Wu , M. T. Hershberger , Daixiang Mou , Ben Schrunk , Michael C. Tringides , Myron Hupalo , Adam Kaminski

The enchanting Dirac fermions in graphene stimulated us to seek for other two-dimensional (2D) Dirac materials, and boron monolayers may be a good candidate. So far, a number of monolayer boron sheets have been theoretically predicted, and…

Mesoscale and Nanoscale Physics · Physics 2016-12-28 Honghong Zhang , Yuee Xie , Zhongwei Zhang , Chengyong Zhong , Yafei Li , Zhongfang Chen , Yuanping Chen

We establish an analogy between spectra of Dirac fermions in laser fields and an electron spectrum of graphene superlattices formed by static 1D periodic potentials. The general relations between a laser-controlled spectrum where electron…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Sergey E. Savel'ev , Alexandre S. Alexandrov

Superconductivity of a single two-dimensional Dirac fermion offers a natural route to topological superconductivity. While usually considered extrinsic -- arising from proximity to a conventional superconductor -- we investigate when a…

Superconductivity · Physics 2026-04-09 Omid Tavakol , Thomas Scaffidi

The emergence of a flat band in Dirac-Weyl materials offers new possibilities for electronic transitions, leading to stronger interaction with light. As a result, the optical conductivity can be significantly enhanced in these flat-band…

Optics · Physics 2024-02-23 Li-Li Ye , Chen-Di Han , Ying-Cheng Lai

We study the electric-field tunable electronic properties of phosphorene thin films, using the framework of density functional theory. We show that phosphorene thin films offer a versatile material platform to study two dimensional Dirac…

Mesoscale and Nanoscale Physics · Physics 2016-11-30 Barun Ghosh , Bahadur Singh , R. Prasad , Amit Agarwal

It is shown, for the first time, that the zitterbewegung of photon can appear near the Dirac point in two-dimensional photonic crystal. The superiority of such a phenomenon for photons is that it can be found in different scaling structures…

Optics · Physics 2009-11-13 Xiangdong Zhang

Gap opening in graphene is usually discussed in terms of a semiconducting-like spectrum, where the appearance of a finite gap at the Dirac point is accompanied by a finite mass for the fermions. In this Letter we propose a gap scenario from…

Mesoscale and Nanoscale Physics · Physics 2008-10-03 L. Benfatto , E. Cappelluti

Dirac cones are conical singularities that occur near the degenerate points in band structures. Such singularities result in enormous unusual phenomena of the corresponding physical systems. This work investigates double Dirac cones that…

Mathematical Physics · Physics 2023-08-21 Ying Cao , Yi Zhu

The spin-orbit interaction of light is a crucial concept for understanding the electromagnetic properties of a material and realizing the spin-controlled manipulation of optical fields. Achieving these goals requires a complete description…

Optics · Physics 2022-11-08 Longlong Feng , Qianfan Wu

Two-dimensional (2D) materials may exhibit intriguing band structure features (e.g., Dirac points), that lay far away from the Fermi level. They are, thus, not usable in applications. The semiconducting 2D material PC6 has two Dirac cones…

Materials Science · Physics 2021-10-01 Maximilian A. Springer , Thomas Brumme , Agnieszka Kuc , Thomas Heine