Weyl, Dirac and high-fold chiral fermions in topological quantum materials.
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TLDR
A review of Weyl-line phases in magnetic topological materials can be found in this article, where the authors provide an introduction to the basic concepts underlying Weyl physics in condensed matter and to representative materials and their electronic structures and topology as revealed by spectroscopic studies.Abstract:
Quantum materials hosting Weyl fermions have opened a new era of research in condensed matter physics. First proposed in 1929 in particle physics, Weyl fermions have yet to be observed as elementary particles. In 2015, Weyl fermions were detected as collective electronic excitations in the strong spin-orbit coupled material tantalum arsenide, TaAs. This discovery was followed by a flurry of experimental and theoretical explorations of Weyl phenomena in materials. Weyl materials naturally lend themselves to the exploration of the topological index associated with Weyl fermions and their divergent Berry curvature field, as well as the topological bulk-boundary correspondence giving rise to protected conducting surface states. Here, we review the broader class of Weyl topological phenomena in materials, starting with the observation of emergent Weyl fermions in the bulk and of Fermi arc states on the surface of the TaAs family of crystals by photoemission spectroscopy. We then discuss some of the exotic optical and magnetic responses observed in these materials, as well as the progress in developing some of the related chiral materials. We discuss the conceptual development of high-fold chiral fermions, which generalize Weyl fermions, and we review the observation of high-fold chiral fermion phases by taking the rhodium silicide, RhSi, family of crystals as a prime example. Lastly, we discuss recent advances in Weyl-line phases in magnetic topological materials. With this Review, we aim to provide an introduction to the basic concepts underlying Weyl physics in condensed matter, and to representative materials and their electronic structures and topology as revealed by spectroscopic studies. We hope this work serves as a guide for future theoretical and experimental explorations of chiral fermions and related topological quantum systems with potentially enhanced functionalities.read more
Citations
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Topological Phase and Quantum Anomalous Hall Effect in Ferromagnetic Transition-Metal Dichalcogenides Monolayer 1T-VSe2.
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Type-II Weyl semimetal vs gravastar.
Grigory Volovik,Grigory Volovik +1 more
TL;DR: In this article, the authors proposed to study the vacuum structure of the type II gravastar using the $q$-theory, where the vacuum variable is the 4-form field introduced for the phenomenological description of the quantum vacuum.
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Terahertz Nonlinear Hall Rectifiers Based on Spin-Polarized 1T-CoTe2.
Zhen Hu,Libo Zhang,Atasi Chakraborty,Gianluca D'Olimpio,Jun Fujii,Anping Ge,Yuanchen Zhou,Changlong Liu,Amit Agarwal,Ivana Vobornik,Daniel Farías,Chia Nung Kuo,Chin-Shan Lue,Antonio Politano,Shao-Wei Wang,Weida Hu,Xiaoshuang Chen,Wei Lu,Lin Wang +18 more
TL;DR: In this article , the second-order nonlinear Hall effect (NLHE) was observed in a type-II Dirac semimetal CoTe2 under time-reversal symmetry.
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Intertwining of Magnetism and Charge Ordering in Kagome FeGe.
S. M. Shao,Jiaxin Yin,Ilya Belopolski,Jing-Yang You,Tao Hou,Hongyu Chen,Yu Xiao Jiang,Md. Shafayat Hossain,M. Yahyavi,Chia-Hsiu Hsu,Yuan Ping Feng,Arun Bansil,M. Z. Hasan,Guoqing Chang +13 more
TL;DR: In this article , the structural and electronic properties of antiferromagnet FeGe have been investigated and it was shown that the 2 × 2 × 1 × 1 charge density wave (CDW) in FeGe likely results from the Fermi surface nesting of hexagonal-prism-shaped kagome states.
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Tunable topologically driven Fermi arc van Hove singularities
Daniel S. Sanchez,Tyler A. Cochran,Ilya Belopolski,Zijia Cheng,Xian P. Yang,Yiyuan Liu,Tao Hou,Xitong Xu,Kaustuv Manna,Chandra Shekhar,Jiaxin Yin,Horst Borrmann,Alla Chikina,Jonathan D. Denlinger,Vladimir N. Strocov,Weiwei Xie,Claudia Felser,Shuang Jia,Guoqing Chang,M. Z. Hasan +19 more
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