scholarly journals Time-reversal invariant realization of the Weyl semimetal phase

2012 ◽  
Vol 85 (3) ◽  
Author(s):  
Gábor B. Halász ◽  
Leon Balents
Keyword(s):  
Time Reversal ◽  
Weyl Semimetal

scholarly journals Signatures of a time-reversal symmetric Weyl semimetal with only four Weyl points

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Ilya Belopolski ◽  
Peng Yu ◽  
Daniel S. Sanchez ◽  
Yukiaki Ishida ◽  
Tay-Rong Chang ◽  
...  
Keyword(s):  
Time Reversal ◽  
Weyl Semimetal

scholarly journals Nontrivial Berry phase in magnetic BaMnSb2 semimetal

2017 ◽  
Vol 114 (24) ◽  
pp. 6256-6261 ◽  
Author(s):  
Silu Huang ◽  
Jisun Kim ◽  
W. A. Shelton ◽  
E. W. Plummer ◽  
Rongying Jin
Keyword(s):  
Time Reversal ◽  
Berry Phase ◽  
High Mobility ◽  
Type I ◽  
Topological Superconductors ◽  
Weyl Semimetal ◽  
Antiferromagnetic Ordering ◽  
Ferromagnetic Ordering ◽  
2D And 3D ◽  
Weyl Fermions

The subject of topological materials has attracted immense attention in condensed-matter physics because they host new quantum states of matter containing Dirac, Majorana, or Weyl fermions. Although Majorana fermions can only exist on the surface of topological superconductors, Dirac and Weyl fermions can be realized in both 2D and 3D materials. The latter are semimetals with Dirac/Weyl cones either not tilted (type I) or tilted (type II). Although both Dirac and Weyl fermions have massless nature with the nontrivial Berry phase, the formation of Weyl fermions in 3D semimetals require either time-reversal or inversion symmetry breaking to lift degeneracy at Dirac points. Here we demonstrate experimentally that canted antiferromagnetic BaMnSb2 is a 3D Weyl semimetal with a 2D electronic structure. The Shubnikov–de Hass oscillations of the magnetoresistance give nearly zero effective mass with high mobility and the nontrivial Berry phase. The ordered magnetic arrangement (ferromagnetic ordering in the ab plane and antiferromagnetic ordering along the c axis below 286 K) breaks the time-reversal symmetry, thus offering us an ideal platform to study magnetic Weyl fermions in a centrosymmetric material.

scholarly journals Weyl semimetal with broken time reversal and inversion symmetries

2012 ◽  
Vol 85 (16) ◽  
Author(s):  
A. A. Zyuzin ◽  
Si Wu ◽  
A. A. Burkov
Keyword(s):  
Time Reversal ◽  
Weyl Semimetal ◽  
And Inversion

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 Kramers Weyl semimetals as quantum solenoids and their applications in spin-orbit torque devices

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Wen-Yu He ◽  
Xiao Yan Xu ◽  
K. T. Law
Keyword(s):  
Time Reversal ◽  
Perpendicular Magnetic Anisotropy ◽  
Spin Orbit ◽  
Longitudinal Magnetization ◽  
Spin Magnetization ◽  
Weyl Semimetal ◽  
Electric Control ◽  
Lattice Symmetry ◽  
Weyl Semimetals ◽  
Chiral Crystals

AbstractKramers Weyl semimetals are Weyl semimetals that have Weyl points pinned at the time reversal invariant momenta. Recently it has been discovered that all chiral crystals host Weyl points at time reversal invariant momenta, so metals with chiral lattice symmetry all belong to the category of Kramers Weyl semimetals. In this work, we show that due to the chiral lattice symmetry, Kramers Weyl semimetals have the unique longitudinal magnetoelectric effect in which the charge current induced spin and orbital magnetization is parallel to the direction of the current. This feature allows Kramers Weyl semimetals to act as nanoscale quantum solenoids with both orbital and spin magnetization. As the moving electrons of Kramers Weyl semimetal can generate longitudinal magnetization, Kramers Weyl semimetals can be used for new designs of spin-orbit torque devices with all electric control of magnetization switching for magnets with perpendicular magnetic anisotropy.

scholarly journals Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd2As2

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw4718 ◽  
Author(s):  
J.-Z. Ma ◽  
S. M. Nie ◽  
C. J. Yi ◽  
J. Jandke ◽  
T. Shang ◽  
...  
Keyword(s):  
Long Range ◽  
Time Reversal ◽  
Spin Fluctuation ◽  
Paramagnetic Phase ◽  
Spontaneous Breaking ◽  
Time Reversal Symmetry ◽  
Energy Bands ◽  
Range Magnetic Order ◽  
Weyl Semimetal ◽  
Long Range Magnetic Order

Weyl fermions as emergent quasiparticles can arise in Weyl semimetals (WSMs) in which the energy bands are nondegenerate, resulting from inversion or time-reversal symmetry breaking. Nevertheless, experimental evidence for magnetically induced WSMs is scarce. Here, using photoemission spectroscopy, we observe that the degeneracy of Bloch bands is already lifted in the paramagnetic phase of EuCd2As2. We attribute this effect to the itinerant electrons experiencing quasi-static and quasi–long-range ferromagnetic fluctuations. Moreover, the spin-nondegenerate band structure harbors a pair of ideal Weyl nodes near the Fermi level. Hence, we show that long-range magnetic order and the spontaneous breaking of time-reversal symmetry are not essential requirements for WSM states in centrosymmetric systems and that WSM states can emerge in a wider range of condensed matter systems than previously thought.

Topological Weyl semimetal phases in a time reversal invariant spinless model

2020 ◽  
Vol 32 (32) ◽  
pp. 325501
Author(s):  
Kangkang Li ◽  
Shengshan Qin ◽  
Peiyuan Fu
Keyword(s):  
Time Reversal ◽  
Weyl Semimetal
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