Observation of Weyl nodes in TaAs
B. Q. Lv,B. Q. Lv,Nan Xu,Nan Xu,Hongming Weng,Junzhang Ma,Junzhang Ma,Pierre Richard,Xiong Huang,Lin Zhao,Genfu Chen,Christian Matt,Federico Bisti,Vladimir N. Strocov,Joël Mesot,Joël Mesot,Joël Mesot,Zhong Fang,Xi Dai,Tian Qian,Ming Shi,Hong Ding +21 more
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TLDR
In this article, the authors reported the direct observation in TaAs of the long-sought-after Weyl nodes by performing bulk-sensitive soft X-ray angle-resolved photoemission spectroscopy measurements.Abstract:
Experiments show that TaAs is a three-dimensional topological Weyl semimetal. In 1929, H. Weyl proposed that the massless solution of the Dirac equation represents a pair of a new type of particles, the so-called Weyl fermions1. However, their existence in particle physics remains elusive after more than eight decades. Recently, significant advances in both topological insulators and topological semimetals have provided an alternative way to realize Weyl fermions in condensed matter, as an emergent phenomenon: when two non-degenerate bands in the three-dimensional momentum space cross in the vicinity of the Fermi energy (called Weyl nodes), the low-energy excitations behave exactly as Weyl fermions. Here we report the direct observation in TaAs of the long-sought-after Weyl nodes by performing bulk-sensitive soft X-ray angle-resolved photoemission spectroscopy measurements. The projected locations at the nodes on the (001) surface match well to the Fermi arcs, providing undisputable experimental evidence for the existence of Weyl fermionic quasiparticles in TaAs.read more
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Nonsymmorphic symmetry protected node-line semimetal in the trigonal YH3
TL;DR: The surface states of this trigonal YH3 at ambient pressure are somehow unique and may be helpful to identify the real ground state of YH2 in the experiment and a good candidate for experimental explorations on the fundamental physics of topological node-line semimetals.
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First-principles calculations for the effect of energetic point defect formation on electronic properties of the Weyl MX family (M = Nb, Ta; X = P, As)
Sami Ullah,Sajjad Shakir Ali,Aziz Ahmad,Nabi Ullah,Jabir Hakami,Muhammad Usman,Sikandar Khan,Firoz Khan +7 more
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Observation of an unexpected negative magnetoresistance in magnetic Weyl semimetal Co3Sn2S2
Ali G. Moghaddam,Kevin Geishendorf,Richard Schlitz,Jorge I. Facio,Praveen Vir,Chandra Shekhar,Claudia Felser,Kornelius Nielsch,Sebastian T. B. Goennenwein,Jeroen van den Brink,Andy Thomas +10 more
TL;DR: In this article , the transverse and longitudinal transport properties of the magnetic Weyl system were investigated and the presence of magnetoresistance up to 1 % with a strong anisotropy depending on the projection of the easy-axis magnetization.
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Noncentrosymmetric Weyl phase and topological phase transition in bulk MoTe.
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Theoretical study of HgCr2Se3.5Te0.5: a doping-site-dependent semimetal.
TL;DR: Detailed first-principles and theoretical studies on HgCr2Se4 with doping of Te atoms at the Se sites find that when the type of doping induces inversion symmetry or positional disorder, the Weyl nodes transform into Dirac points resulting in a change from a WeylSemimetal to a Dirac semimetal.
References
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Topological semimetal and Fermi-arc surface states in the electronic structure of pyrochlore iridates
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TL;DR: In this paper, the topological semimetal, a three-dimensional phase of a magnetic solid, is described and it may be realized in a class of pyrochlore iridates based on calculations using the LDA+U$ method.
Journal ArticleDOI
Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
Su-Yang Xu,Ilya Belopolski,Nasser Alidoust,Madhab Neupane,Chenglong Zhang,Raman Sankar,Shin-Ming Huang,Chi-Cheng Lee,Guoqing Chang,Baokai Wang,Guang Bian,Hao Zheng,Daniel S. Sanchez,Fangcheng Chou,Hsin Lin,Shuang Jia,M. Zahid Hasan +16 more
TL;DR: The experimental discovery of a Weyl semimetal, tantalum arsenide (TaAs), using photoemission spectroscopy, which finds that Fermi arcs terminate on the Weyl fermion nodes, consistent with their topological character.
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Electronic Structure of Pyrochlore Iridates: From Topological Dirac Metal to Mott Insulator
TL;DR: In this article, the electronic structure of pyrochlore iridates was investigated using density functional theory, LDA+U method, and effective low energy models, and a remarkably rich phase diagram emerges on tuning the correlation strength U.
Journal ArticleDOI
Discovery of a Weyl fermion semimetal and topological Fermi arcs
Su-Yang Xu,Ilya Belopolski,Nasser Alidoust,Madhab Neupane,Madhab Neupane,Guang Bian,Chenglong Zhang,Raman Sankar,Guoqing Chang,Zhujun Yuan,Chi-Cheng Lee,Shin-Ming Huang,Hao Zheng,Jie Ma,Daniel S. Sanchez,Baokai Wang,Baokai Wang,Arun Bansil,Fangcheng Chou,Pavel Shibayev,Hsin Lin,Shuang Jia,M. Zahid Hasan +22 more
TL;DR: In this article, the experimental discovery of a Weyl semimetal, tantalum arsenide (TaAs), was reported, which is a new state of matter that hosts Weyl fermions as emergent quasiparticles and admits a topological classification that protects Fermi arcs on the boundary of a bulk sample.
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