scholarly journals Signature of Fermi arc surface states in Andreev reflection at the WTe 2 Weyl semimetal surface

2018 ◽  
Vol 122 (2) ◽  
pp. 27004 ◽  
Author(s):  
A. Kononov ◽  
O. O. Shvetsov ◽  
S. V. Egorov ◽  
A. V. Timonina ◽  
N. N. Kolesnikov ◽  
...  
Keyword(s):  
Andreev Reflection ◽  
Surface States ◽  
Fermi Arc ◽  
Weyl Semimetal

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 Andreev reflection in Fermi-arc surface states of Weyl semimetals

2021 ◽  
Vol 104 (7) ◽  
Author(s):  
Yue Zheng ◽  
Wei Chen ◽  
D. Y. Xing
Keyword(s):  
Andreev Reflection ◽  
Surface States ◽  
Fermi Arc ◽  
Weyl Semimetals

scholarly journals Realization of a Double-Slit SQUID Geometry by Fermi Arc Surface States in a WTe2 Weyl Semimetal

JETP Letters ◽  
2018 ◽  
Vol 107 (12) ◽  
pp. 774-779 ◽  
Author(s):  
O. O. Shvetsov ◽  
A. Kononov ◽  
A. V. Timonina ◽  
N. N. Kolesnikov ◽  
E. V. Deviatov
Keyword(s):  
Surface States ◽  
Fermi Arc ◽  
Weyl Semimetal ◽  
Double Slit

The Generation of Switchable Polarized Currents in Nodal Ring Semimetals Using High-Frequency Periodic Driving

2021 ◽  
Author(s):  
Pei-Hao Fu ◽  
Qianqian Lv ◽  
Xiang-Long Yu ◽  
Jun-Feng Liu ◽  
Jiansheng Wu
Keyword(s):  
High Frequency ◽  
Surface Currents ◽  
Switching Effect ◽  
Fermi Arc ◽  
Periodically Driven ◽  
Weyl Semimetal ◽  
Spin Polarized ◽  
High Frequency Electromagnetic Field ◽  
Polarized Surface ◽  
Lead Device

Abstract A nodal ring semimetal (NRSM) can be driven to a spin-polarized NRSM or a spin-polarized Weyl semimetal (SWSM) by a high-frequency electromagnetic field. We investigate the conditions in realizing these phases and propose a switchable spin-polarized currents generator based on periodically driven NRSMs. Both bulk and surface polarized currents are investigated. The polarization of bulk current is sensitive to the amplitude of the driving field and robust against the direction and polarization of the driving, the opaqueness of the lead-device interface and the misalignment between the nodal ring and the interface, which provides sufficient flexibility in manipulating the devices. Similar switchable polarized surface currents are also expected, which is contributed by the Fermi arc surface state associated with the Weyl semimetal (WSM) phases. The generation of polarized currents and the polarization switching effect offer opportunities to design periodic driving controlled topological spintronics devices based on NRSMs.

scholarly journals Exceptional topological insulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Michael Denner ◽  
Anastasiia Skurativska ◽  
Frank Schindler ◽  
Mark H. Fischer ◽  
Ronny Thomale ◽  
...  
Keyword(s):  
Topological Insulator ◽  
Three Dimensional ◽  
Surface States ◽  
Exceptional Point ◽  
Weyl Semimetal ◽  
Complex Eigenvalues ◽  
Topological State ◽  
Single Sheet ◽  
Bulk Energy ◽  
State Of Matter

AbstractWe introduce the exceptional topological insulator (ETI), a non-Hermitian topological state of matter that features exotic non-Hermitian surface states which can only exist within the three-dimensional topological bulk embedding. We show how this phase can evolve from a Weyl semimetal or Hermitian three-dimensional topological insulator close to criticality when quasiparticles acquire a finite lifetime. The ETI does not require any symmetry to be stabilized. It is characterized by a bulk energy point gap, and exhibits robust surface states that cover the bulk gap as a single sheet of complex eigenvalues or with a single exceptional point. The ETI can be induced universally in gapless solid-state systems, thereby setting a paradigm for non-Hermitian topological matter.

Nonlinear nanoelectrodynamics of a Weyl metal

2021 ◽  
Vol 118 (48) ◽  
pp. e2116366118
Author(s):  
Yinming Shao ◽  
Ran Jing ◽  
Sang Hoon Chae ◽  
Chong Wang ◽  
Zhiyuan Sun ◽  
...  
Keyword(s):  
Electric Fields ◽  
Mirror Symmetry ◽  
Density Functional ◽  
Near Field ◽  
Surface States ◽  
Real Space ◽  
Resonance Structure ◽  
Nonlinear Conductivity ◽  
Weyl Semimetal ◽  
Photocurrent Spectroscopy

Chiral Weyl fermions with linear energy-momentum dispersion in the bulk accompanied by Fermi-arc states on the surfaces prompt a host of enticing optical effects. While new Weyl semimetal materials keep emerging, the available optical probes are limited. In particular, isolating bulk and surface electrodynamics in Weyl conductors remains a challenge. We devised an approach to the problem based on near-field photocurrent imaging at the nanoscale and applied this technique to a prototypical Weyl semimetal TaIrTe4. As a first step, we visualized nano-photocurrent patterns in real space and demonstrated their connection to bulk nonlinear conductivity tensors through extensive modeling augmented with density functional theory calculations. Notably, our nanoscale probe gives access to not only the in-plane but also the out-of-plane electric fields so that it is feasible to interrogate all allowed nonlinear tensors including those that remained dormant in conventional far-field optics. Surface- and bulk-related nonlinear contributions are distinguished through their “symmetry fingerprints” in the photocurrent maps. Robust photocurrents also appear at mirror-symmetry breaking edges of TaIrTe4 single crystals that we assign to nonlinear conductivity tensors forbidden in the bulk. Nano-photocurrent spectroscopy at the boundary reveals a strong resonance structure absent in the interior of the sample, providing evidence for elusive surface states.

scholarly journals Robust edge photocurrent response on layered type II Weyl semimetal WTe2

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Qinsheng Wang ◽  
Jingchuan Zheng ◽  
Yuan He ◽  
Jin Cao ◽  
Xin Liu ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Surface States ◽  
Separation Mechanism ◽  
Current Response ◽  
Type Ii ◽  
Nonlinear Optical Effect ◽  
Linear Dispersion ◽  
Weyl Semimetal ◽  
Quantum Materials ◽  
A Charge

AbstractPhotosensing and energy harvesting based on exotic properties of quantum materials and new operation principles have great potential to break the fundamental performance limit of conventional photodetectors and solar cells. Weyl semimetals have demonstrated novel optoelectronic properties that promise potential applications in photodetection and energy harvesting arising from their gapless linear dispersion and Berry field enhanced nonlinear optical effect at the vicinity of Weyl nodes. In this work, we demonstrate robust photocurrent generation at the edge of Td-WTe2, a type-II Weyl semimetal, due to crystalline-symmetry breaking along certain crystal fracture directions and possibly enhanced by robust fermi-arc type surface states. This edge response is highly generic and arises universally in a wide class of quantum materials with similar crystal symmetries. The robust and generic edge current response provides a charge separation mechanism for photosensing and energy harvesting over broad wavelength range.

Andreev reflection in nodal-line Weyl semimetal

2020 ◽  
Vol 32 (18) ◽  
pp. 185001
Author(s):  
Chunxu Bai ◽  
Yanling Yang
Keyword(s):  
Andreev Reflection ◽  
Nodal Line ◽  
Weyl Semimetal
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