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Weyl semimetals are a class of materials that can be regarded as three-dimensional analogs of graphene breaking time reversal or inversion symmetry. Electrons in a Weyl semimetal behave as Weyl fermions, which have many exotic properties,…

Materials Science · Physics 2015-08-05 B. Q. Lv , H. M. Weng , B. B. Fu , X. P. Wang , H. Miao , J. Ma , P. Richard , X. C. Huang , L. X. Zhao , G. F. Chen , Z. Fang , X. Dai , T. Qian , H. Ding

The chiral surface states of Weyl semimetals have an open Fermi surface called Fermi arc. At the interface between two Weyl semimetals, these Fermi arcs are predicted to hybridize and alter their connectivity. In this letter, we numerically…

Mesoscale and Nanoscale Physics · Physics 2023-08-07 D. -H. -Minh Nguyen , Chiara Devescovi , Dung Xuan Nguyen , Hai Son Nguyen , Dario Bercioux

The recent discovery of Weyl fermions in solids enables exploitation of relativistic physics and development of a spectrum of intriguing physical phenomena. They are constituted of pairs of Weyl points with two-fold band degeneracy, which…

We report the discovery of a time-reversal symmetric Weyl semimetal obtained by modifying a model Hamiltonian describing the electronic properties of conventional alkali metals. The artificially generated Weyl semimetal features four…

Materials Science · Physics 2020-06-11 Joseba Goikoetxea , Jorge Bravo-Abad , Jaime Merino

Kelvin probe force microscopy (KPFM) has been employed to probe charge carriers in a graphene/hexagonal boron nitride (hBN) heterostructure [Nano Lett, 21, 5013 (2021)]. We propose an approach for operating valley filtering based on the…

Mesoscale and Nanoscale Physics · Physics 2023-10-19 A. Belayadi , N. A. Hadadi , P. Vasilopoulos , A. Abbout

We study theoretically the electron current across a monolayer graphene/hexagonal boron nitride/bilayer graphene tunnelling junction in an external magnetic field perpendicular to the layers. We show that change in effective tunnelling…

Mesoscale and Nanoscale Physics · Physics 2019-02-18 J. J . P. Thompson , D. J. Leech , M. Mucha-Kruczyński

Electrons in graphene, in addition to their spin, have two pseudospin degrees of freedom: sublattice and valley pseudospin. Valleytronics uses the valley degree of freedom as a carrier of information similar to the way spintronics uses…

Mesoscale and Nanoscale Physics · Physics 2013-04-03 D. Moldovan , M. Ramezani Masir , L. Covaci , F. M. Peeters

In addition to electron charge and spin, novel materials host another degree of freedom, the valley. For a junction composed of valley filter sandwiched by two normal terminals, we focus on the valley efficiency under disorder with two…

Mesoscale and Nanoscale Physics · Physics 2017-11-29 Shu-guang Cheng , Jiaojiao Zhou , Hua Jiang , Qing-Feng Sun

We extend the study of fermionic particle-hole symmetric semi-Dirac (alternatively, semi-Weyo) dispersion of quasiparticles, $\varepsilon_K = \pm \sqrt{(k_x^2/2m)^2 + (vk_y)^2)} = \pm \varepsilon_0 \sqrt{K_x^4 + K_y^2}$ in dimensionless…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Swapnonil Banerjee , Warren E. Pickett

We investigate magnetotransport across an interface between two Weyl semimetals (finite in both directions) whose Weyl nodes project onto two different surfaces which are twisted with respect to each other before being coupled. This gives…

Mesoscale and Nanoscale Physics · Physics 2025-11-20 Nirnoy Basak , Sumathi Rao , Faruk Abdulla

Weyl semimetals harbor unusual surface states known as Fermi arcs, which are essentially disjoint segments of a two dimensional Fermi surface. We describe a prescription for obtaining Fermi arcs of arbitrary shape and connectivity by…

Strongly Correlated Electrons · Physics 2012-11-08 Pavan Hosur

The energy spectrum of graphene sheet with a single barrier structure having a time periodic oscillating height and subjected to magnetic field is analyzed. The corresponding transmission is studied as function of the obtained energy and…

Mesoscale and Nanoscale Physics · Physics 2015-06-18 Ahmed Jellal , Miloud Mekkaoui , El Bouazzaoui Choubabi , Hocine Bahlouli

Weyl semimetals are characterized by their bulk Weyl points -- conical band touching points that carry a topological monopole charge -- and Fermi arc states that span between the Weyl points on the surface of the material. Recently,…

Mesoscale and Nanoscale Physics · Physics 2020-03-13 Guangze Chen , Wei Chen , Oded Zilberberg

Elastic deformations of graphene can significantly change the flow paths and valley polarization of the electric currents. We investigate these phenomena in graphene nanoribbons with localized out-of-plane deformations by means of…

Mesoscale and Nanoscale Physics · Physics 2019-03-12 Thomas Stegmann , Nikodem Szpak

Valley-polarized currents can be generated by local straining of multi-terminal graphene devices. The pseudo-magnetic field created by the deformation allows electrons from only one valley to transmit and a current of electrons from a…

Mesoscale and Nanoscale Physics · Physics 2016-11-18 S. P. Milovanovic , F. M. Peeters

Dirac and Weyl nodal materials can host low-energy relativistic quasiparticles. Under strong magnetic fields, the topological properties of Dirac/Weyl materials can directly manifest through quantum Hall states. However, most Dirac/Weyl…

Mesoscale and Nanoscale Physics · Physics 2020-08-11 Gang Qiu , Chang Niu , Yixiu Wang , Mengwei Si , Zhuocheng Zhang , Wenzhuo Wu , Peide D. Ye

Weyl semimetals are a new paradigmatic topological phase of matter featuring a gapless spectrum. One of its most distinctive features is the presence of Fermi arc surface states. Here, we report on atomistic simulations of the dc…

Mesoscale and Nanoscale Physics · Physics 2018-03-20 Jose Chesta Lopez , Luis E. F. Foa Torres , Alvaro S. Nunez

Topological Weyl semimetals represent a novel class of non-trivial materials, where band crossings with linear dispersions take place at generic momenta across reciprocal space. These crossings give rise to low-energy properties akin to…

Materials Science · Physics 2024-02-12 Davide Grassano , Nicola Marzari , Davide Campi

A two-dimensional (2D) Weyl semimetal featuring a spin-polarized linear band dispersion and a nodal Fermi surface is a new topological phase of matter. It is a solid-state realization of Weyl fermions in an intrinsic 2D system. The…

Periodically driven systems provide tunable platforms to realize interesting Floquet topological phases and phase transitions. In electronic systems with Weyl dispersions, the band crossings are topologically protected even in the presence…

Mesoscale and Nanoscale Physics · Physics 2016-09-14 Ching-Kit Chan , Yun-Tak Oh , Jung Hoon Han , Patrick A. Lee