scholarly journals Helical Fermi arcs and surface states in time-reversal invariant Weyl semimetals

2013 ◽  
Vol 87 (24) ◽  
Author(s):  
Teemu Ojanen
Keyword(s):  
Time Reversal ◽  
Surface States ◽  
Fermi Arcs ◽  
Weyl Semimetals

scholarly journals Fermi-arc diversity on surface terminations of the magnetic Weyl semimetal Co3Sn2S2

Science ◽  
2019 ◽  
Vol 365 (6459) ◽  
pp. 1286-1291 ◽  
Author(s):  
Noam Morali ◽  
Rajib Batabyal ◽  
Pranab Kumar Nag ◽  
Enke Liu ◽  
Qiunan Xu ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Time Reversal ◽  
Surface States ◽  
Time Reversal Symmetry ◽  
Fermi Arc ◽  
Weyl Semimetal ◽  
Fermi Arcs ◽  
Bulk Surface ◽  
Weyl Semimetals ◽  
Node Connectivity

Bulk–surface correspondence in Weyl semimetals ensures the formation of topological “Fermi arc” surface bands whose existence is guaranteed by bulk Weyl nodes. By investigating three distinct surface terminations of the ferromagnetic semimetal Co3Sn2S2, we verify spectroscopically its classification as a time-reversal symmetry-broken Weyl semimetal. We show that the distinct surface potentials imposed by three different terminations modify the Fermi-arc contour and Weyl node connectivity. On the tin (Sn) surface, we identify intra–Brillouin zone Weyl node connectivity of Fermi arcs, whereas on cobalt (Co) termination, the connectivity is across adjacent Brillouin zones. On the sulfur (S) surface, Fermi arcs overlap with nontopological bulk and surface states. We thus resolve both topologically protected and nonprotected electronic properties of a Weyl semimetal.

scholarly journals A Primer on Weyl Semimetals: Down the Discovery of Topological Phases

2021 ◽  
pp. 34-45
Author(s):  
Satyaki Kar ◽  
Arun M. Jayannavar
Keyword(s):  
Magnetic Monopole ◽  
Condensed Matter ◽  
Surface States ◽  
Berry Curvature ◽  
Fermi Arcs ◽  
Electric And Magnetic Fields ◽  
Weyl Semimetals ◽  
Topological Surface ◽  
Bulk Energy ◽  
Basic Features

Recently discovered Weyl semimetals (WSM) have found special place in topological condensed matter studies for they represent first example of massless Weyl fermions found in electronic condensed matter systems. A WSM shows gapless bulk energy spectra with Dirac-like point degeneracies, famously called Weyl nodes, which carry with themselves well defined chiralities and topologically protected chiral charges. One finds the Berry curvature of the Bloch bands to become singular, like in a magnetic monopole, at these Weyl nodes. Moreover, these systems feature topological surface states in the form of open Fermi arcs. In this review, we undergo a concise journey from graphene based Dirac physics to Weyl semimetals: the underlying Hamiltonians, their basic features and their unique response to external electric and magnetic fields in order to provide a basic walk-through of how the Weyl physics unfolded with time starting from the discovery of Graphene.

scholarly journals Dirac semimetal in β-CuI without surface Fermi arcs

2018 ◽  
Vol 115 (33) ◽  
pp. 8311-8315 ◽  
Author(s):  
Congcong Le ◽  
Xianxin Wu ◽  
Shengshan Qin ◽  
Yinxiang Li ◽  
Ronny Thomale ◽  
...  
Keyword(s):  
First Principles ◽  
Surface States ◽  
Energy Difference ◽  
First Principles Calculations ◽  
Small Energy ◽  
Concrete Material ◽  
Dirac Semimetal ◽  
Fermi Arcs ◽  
Anomalous Surface ◽  
Weyl Semimetals

Anomalous surface states with Fermi arcs are commonly considered to be a fingerprint of Dirac semimetals (DSMs). In contrast to Weyl semimetals, however, Fermi arcs of DSMs are not topologically protected. Using first-principles calculations, we predict that β-cuprous iodide (β-CuI) is a peculiar DSM whose surface states form closed Fermi pockets instead of Fermi arcs. In such a fermiological Dirac semimetal, the deformation mechanism from Fermi arcs to Fermi pockets stems from a large cubic term preserving all crystal symmetries and from the small energy difference between the surface and bulk Dirac points. The cubic term in β-CuI, usually negligible in prototypical DSMs, becomes relevant because of the particular crystal structure. As such, we establish a concrete material example manifesting the lack of topological protection for surface Fermi arcs in DSMs.

scholarly journals Generic Coexistence of Fermi Arcs and Dirac Cones on the Surface of Time-Reversal Invariant Weyl Semimetals

2017 ◽  
Vol 119 (7) ◽  
Author(s):  
Alexander Lau ◽  
Klaus Koepernik ◽  
Jeroen van den Brink ◽  
Carmine Ortix
Keyword(s):  
Time Reversal ◽  
Fermi Arcs ◽  
Weyl Semimetals

scholarly journals Discovery of a weak topological insulating state and van Hove singularity in triclinic RhBi2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kyungchan Lee ◽  
Gunnar F. Lange ◽  
Lin-Lin Wang ◽  
Brinda Kuthanazhi ◽  
Thaís V. Trevisan ◽  
...  
Keyword(s):  
Time Reversal ◽  
Topological Insulators ◽  
Dirac Point ◽  
Saddle Points ◽  
Surface States ◽  
Van Hove Singularity ◽  
Space Group ◽  
Topological Materials ◽  
Topological Surface ◽  
Optimal Space

AbstractTime reversal symmetric (TRS) invariant topological insulators (TIs) fullfil a paradigmatic role in the field of topological materials, standing at the origin of its development. Apart from TRS protected strong TIs, it was realized early on that more confounding weak topological insulators (WTI) exist. WTIs depend on translational symmetry and exhibit topological surface states only in certain directions making it significantly more difficult to match the experimental success of strong TIs. We here report on the discovery of a WTI state in RhBi2 that belongs to the optimal space group P$$\bar{1}$$ 1 ¯ , which is the only space group where symmetry indicated eigenvalues enumerate all possible invariants due to absence of additional constraining crystalline symmetries. Our ARPES, DFT calculations, and effective model reveal topological surface states with saddle points that are located in the vicinity of a Dirac point resulting in a van Hove singularity (VHS) along the (100) direction close to the Fermi energy (EF). Due to the combination of exotic features, this material offers great potential as a material platform for novel quantum effects.

scholarly journals Global topology of Weyl semimetals and Fermi arcs

2017 ◽  
Vol 50 (11) ◽  
pp. 11LT01 ◽  
Author(s):  
Varghese Mathai ◽  
Guo Chuan Thiang
Keyword(s):  
Fermi Arcs ◽  
Global Topology ◽  
Weyl Semimetals

scholarly journals Time-reversal-invariant topological superconductivity in doped Weyl semimetals

2014 ◽  
Vol 90 (4) ◽  
Author(s):  
Pavan Hosur ◽  
Xi Dai ◽  
Zhong Fang ◽  
Xiao-Liang Qi
Keyword(s):  
Time Reversal ◽  
Weyl Semimetals ◽  
Topological Superconductivity
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