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
Citations
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Criteria for Directly Detecting Topological Fermi Arcs in Weyl Semimetals.
Ilya Belopolski,Su-Yang Xu,Daniel S. Sanchez,Guoqing Chang,Cheng Guo,Madhab Neupane,Madhab Neupane,Hao Zheng,Chi-Cheng Lee,Shin-Ming Huang,Guang Bian,Nasser Alidoust,Tay-Rong Chang,Tay-Rong Chang,Baokai Wang,Baokai Wang,Xiao Zhang,Arun Bansil,Horng-Tay Jeng,Horng-Tay Jeng,Hsin Lin,Shuang Jia,M. Zahid Hasan +22 more
TL;DR: It is shown that it is unreasonable to directly observe Fermi arcs in NbP by ARPES within available experimental resolution and spectral linewidth, and rigorously demonstrate a nonzero Chern number in TaAs by counting chiral edge modes on a closed loop.
Journal ArticleDOI
Intrinsic anomalous Hall effect in type-II Weyl semimetals
TL;DR: In this article, the anomalous Hall conductivity of a Weyl semimetal with a tilted conical spectrum for a pair of Weyl points was calculated using the Kubo formula.
Journal ArticleDOI
Optical evidence for a Weyl semimetal state in pyrochlore Eu 2 Ir 2 O 7
Andrei B. Sushkov,Johannes Hofmann,Gregory S. Jenkins,J. J. Ishikawa,Satoru Nakatsuji,Satoru Nakatsuji,S. Das Sarma,H. D. Drew +7 more
TL;DR: In this article, the authors show that the THz optical conductivity and temperature dependence of the free carrier response in pyrochlore iridates match the predictions for a Weyl semimetal and suggest novel Dirac liquid behavior.
Posted Content
Time-Reversal Symmetry Breaking Type-II Weyl State in YbMnBi2
Sergey Borisenko,Daniil Evtushinsky,Quinn Gibson,Alexander Yaresko,Timur K. Kim,Mazhar N. Ali,Bernd Buechner,Moritz Hoesch,Robert J. Cava +8 more
TL;DR: In this paper, the authors used angle-resolved photoemission to detect a time-reversal symmetry breaking Weyl state in a canted antiferromagnetic state and found Weyl points both above and below the Fermi level.
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Dirac line nodes and effect of spin-orbit coupling in the nonsymmorphic critical semimetals MSiS (M = Hf, Zr)
Changkang Chen,X. Xu,Juan Jiang,Juan Jiang,Juan Jiang,Shu-Chun Wu,Yanpeng Qi,Lexian Yang,Meixiao Wang,Yan Sun,Niels B. M. Schröter,Haifeng Yang,Haifeng Yang,Leslie M. Schoop,Yang-Yang Lv,Jian Zhou,Yuhong Chen,Shu-Hua Yao,Ming-Hui Lu,Yan-Feng Chen,Claudia Felser,Binghai Yan,Binghai Yan,Zhe Liu,Yulin Chen,Yulin Chen,Yulin Chen +26 more
TL;DR: In this article, the electronic structure of the nonsymmorphic crystals $M\text{SiS}$ was explored using angle-resolved photoemission spectroscopy (ARPES).
References
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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.
Journal ArticleDOI
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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