Dispersion of Fermi arcs in Weyl semimetals and their evolutions to Dirac cones

The surface Fermi arc states in Z2 Weyl semimetals A3Bi (A = Na, K, Rb) are studied by employing a continuum low-energy effective model. It is shown that the surface Fermi arc states can be classified with respect to the ud-parity symmetry. Because of the symmetry, the arcs come in mirror symmetric pairs. The effects of symmetry breaking terms on the structure of the Fermi arcs are also studied. Among other results, we find at least two qualitatively different types of the surface Fermi arcs. The arcs of the first type link disconnected sheets of the bulk Fermi surface, while arcs of the second type link different points of the same bulk Fermi surface sheet.

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“…28 : v = A and γ = −M 1 . To study the surface Fermi arcs, we will assume that the surface of a semimetal is at y = 0.…”

Section: Surface Fermi Arcs In Simplified 2 × 2 Modelmentioning

confidence: 99%

Surface Fermi arcs inZ2Weyl semimetalsA3Bi(A=Na, K, Rb)

et al. 2015

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“…Recently, there has been a surge of interest in the phase transition of topological semimetals, as studied theoretically [1,[4][5][6][7][8][9][10]. Many exotic physical phenomena, such as quantum criticality [4,8], metal-insulator transitions [7], and evolution of Fermi arc states [9], have been predicted to emerge at the critical transition points of topological semimetals. Despite the theoretical progress, these topological phase transitions remain largely unexplored through experimental study.…”

Section: Introductionmentioning

confidence: 99%

Evidence for pressure-induced node-pair annihilation in Cd3As2

et al. 2017

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We report a magnetotransport study of Dirac semimetal Cd 3 As 2 under high pressure. The Shubnikov-de Haas oscillations are measured at different pressures to reveal the evolution of the Fermi surface. A sudden change in the phase factor of the oscillations occurs at 1.3 GPa along with the unanticipated shrinkage of the Fermi surface, which is well below the structure transition point from the tetragonal to the monoclinic structure (∼2.5 GPa). High-pressure x-ray diffraction also reveals an anisotropic compression of the Cd 3 As 2 lattice around a similar pressure. Through the first-principles calculations, we find that such axial compression along the c direction will shift the Dirac nodes towards the Brillouin zone center and will eventually introduce a finite energy gap. Our result unveils a possible topological phase transition in pressurized Cd 3 As 2 without structure transition.

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“…In non-centrosymmetric Weyl semimetals, different patterns of Fermi arcs on the top and bottom surfaces are theoretically expected [36,37]. Indeed, an ARPES study on NbP [38] revealed the nonequivalent forms of Fermi arcs on respective surfaces, that are terminated at the same 2D projected bulk Weyl nodes.…”

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confidence: 99%

Observation of spin-polarized bands and domain-dependent Fermi arcs in polar Weyl semimetal MoTe2

et al. 2017

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We investigate the surface electronic structures of polar 1T'-MoTe2, the Weyl semimetal candidate realized through the nonpolar-polar structural phase transition, by utilizing the laser angle-resolved photoemission spectroscopy combined with first-principles calculations. Two kinds of domains with different surface band dispersions are observed from a single-crystalline sample. The spin-resolved measurements further reveal that the spin polarizations of the surface and the bulk-derived states show the different domain-dependences, indicating the opposite bulk polarity. For both domains, some segment-like band features resembling the Fermi arcs are clearly observed. The patterns of the arcs present the marked contrast between the two domains, respectively agreeing well with the slab calculation of (0 0 1) and (0 0 -1) surfaces. The present result strongly suggests that the Fermi arc connects the identical pair of Weyl nodes on one side of the polar crystal surface, whereas it connects between the different pairs of Weyl nodes on the other side. Weyl nodes) at the Fermi level (EF). The bulk electronic structure of Weyl semimetals is characterized by the spin-polarized Weyl cone dispersions formed through the breaking of either time-reversal or space-inversion symmetry [1][2][3][4]. At the surface, on the other hand, the chiral charge associated with the Weyl nodes warrants the existence of the gapless surface states, socalled Fermi arcs that connect the two-dimensionally (2D) projected Weyl nodes. Due to these unusual bulk and surface electronic states, a variety of new magnetoelectric phenomena have been predicted [4][5][6][7][8][9]. Until now, several experimental verifications of realistic Weyl semimetal compounds have been raised (eg. the TaAs family [10][11][12] The single-crystalline 1T'-MoTe2 was synthesized as reported elsewhere [19,20].ARPES at 25 K was performed using the He-discharge lamp (21.2 eV) and the fourth harmonic generation of Ti:sapphire laser (6.43 eV, s-polarized light) [28], with a VG-Scienta R4000WALanalyzer. The total energy resolution was set to 10 and 3 meV, respectively. For the laser-SARPES at 25 K and the ARPES at 100 K, a 6.99 eV laser (s-polarized light) and a ScientaOmicron DA30Lanalyzer mounted with two sets of very-low-energy electron diffraction spin detectors were used at the Institute of Solid State Physics (ISSP), The University of Tokyo [29]. The total energy resolution was set to 30 and 3 meV, respectively. Samples were cleaved in situ at room temperature. All measurements were performed in ultrahigh vacuum better than 1×10 -10 Torr.Electronic structure calculations were performed within the context of density functional theory (DFT) using the Perdew-Burke-Ernzerhof exchange-correlation functional as implemented in the VASP program [30,31]. Relativistic effects were fully included. The structure parameters in Ref.[14] were used, and the corresponding Brillouin zone was sampled by a 20 × 10 × 5 k-mesh. To focus on the near-EF electronic structure, the ARPES images...

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Dispersion of Fermi arcs in Weyl semimetals and their evolutions to Dirac cones

Cited by 162 publications

References 22 publications

Surface Fermi arcs inZ2Weyl semimetalsA3Bi(A=Na, K, Rb)

Surface Fermi arcs inZ2Weyl semimetalsA3Bi(A=Na, K, Rb)

Evidence for pressure-induced node-pair annihilation in Cd3As2

Observation of spin-polarized bands and domain-dependent Fermi arcs in polar Weyl semimetal MoTe2

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