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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Dynamics of out-of-equilibrium electron and hole pockets in the type-II Weyl semimetal candidate WTe 2
Marco Caputo,Lama Khalil,Evangelos Papalazarou,N. Nilforoushan,Luca Perfetti,Amina Taleb-Ibrahimi,Quinn Gibson,R. J. Cava,Marino Marsi +8 more
TL;DR: In this paper, a time and angle-resolved photoemission study of the transition-metal dichalcogenide (WTe), a candidate type-II Weyl semimetal exhibiting extremely large magnetoresistence, is presented.
Journal ArticleDOI
Cycling Fermi arc electrons with Weyl orbits
TL;DR: In this article, the authors review the theoretical background and the current experimental status of the Weyl orbit, present the extension of Weyl Orbit physics in realizing the 3D quantum Hall effect, and further discuss the opportunities in tuning topological quantum states and realizing device applications provided by the concept of weyl orbit.
Journal ArticleDOI
Systematic study of stacked square nets: From Dirac fermions to material realizations
TL;DR: In this article, the symmetry-protected nodal fermions that result from different ways of embedding the square net into a larger unit cell were studied, and it was shown that a nonsymmorphic space group is not a necessary condition for a filling enforced semimetal.
Journal ArticleDOI
Uncovering electron-phonon scattering and phonon dynamics in type-I Weyl semimetals
Jennifer Coulter,Gavin B. Osterhoudt,Christina A. C. Garcia,Yiping Wang,Vincent Plisson,Bing Shen,Ni Ni,Kenneth S. Burch,Prineha Narang +8 more
TL;DR: In this paper, the authors used Raman spectroscopy to probe the phonons and electron-phonon coupling in the Weyl semimetals NbAs and TaAs.
Journal ArticleDOI
Topological Singularity Induced Chiral Kohn Anomaly in a Weyl Semimetal.
Thanh D. Nguyen,Fei Han,Nina Andrejevic,Ricardo Pablo-Pedro,Anuj Apte,Yoichiro Tsurimaki,Zhiwei Ding,Kunyan Zhang,Ahmet Alatas,E. Ercan Alp,Songxue Chi,Jaime A. Fernandez-Baca,Masaaki Matsuda,David Tennant,Yang Zhao,Yang Zhao,Zhijun Xu,Zhijun Xu,Jeffrey W. Lynn,Shengxi Huang,Mingda Li +20 more
TL;DR: In this article, a new class of Kohn anomaly in a topological Weyl semimetal (WSM) is reported, where phonon softening can emerge when the phonon wave vector nests the Fermi surface of metals.
References
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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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