TOPOLOGICAL MATTER. Discovery of a Weyl fermion semimetal and topological Fermi arcs

Su-Yang Xu; Ilya Belopolski; Nasser Alidoust; 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; Arun Bansil; Fangcheng Chou; Pavel P Shibayev; Hsin Lin; Shuang Jia; M Zahid Hasan

doi:10.1126/science.aaa9297

TOPOLOGICAL MATTER. Discovery of a Weyl fermion semimetal and topological Fermi arcs

Science. 2015 Aug 7;349(6248):613-7. doi: 10.1126/science.aaa9297. Epub 2015 Jul 16.

Authors

Su-Yang Xu¹, Ilya Belopolski², Nasser Alidoust¹, Madhab Neupane³, Guang Bian², Chenglong Zhang⁴, Raman Sankar⁵, Guoqing Chang⁶, Zhujun Yuan⁴, Chi-Cheng Lee⁶, Shin-Ming Huang⁶, Hao Zheng², Jie Ma⁷, Daniel S Sanchez², BaoKai Wang⁸, Arun Bansil⁹, Fangcheng Chou⁵, Pavel P Shibayev¹⁰, Hsin Lin⁶, Shuang Jia¹¹, M Zahid Hasan¹²

Affiliations

¹ Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA. Princeton Center for Complex Materials, Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ 08544, USA.
² Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA.
³ Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA. Condensed Matter and Magnet Science Group, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
⁴ International Center for Quantum Materials, School of Physics, Peking University, China.
⁵ Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan.
⁶ Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, Singapore 117546. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542.
⁷ Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
⁸ Centre for Advanced 2D Materials and Graphene Research Centre National University of Singapore, 6 Science Drive 2, Singapore 117546. Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542. Department of Physics, Northeastern University, Boston, MA 02115, USA.
⁹ Department of Physics, Northeastern University, Boston, MA 02115, USA.
¹⁰ Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA. Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ 08544, USA.
¹¹ International Center for Quantum Materials, School of Physics, Peking University, China. Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China.
¹² Laboratory for Topological Quantum Matter and Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ 08544, USA. Princeton Center for Complex Materials, Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ 08544, USA. mzhasan@princeton.edu.

PMID: 26184916
DOI: 10.1126/science.aaa9297

Abstract

A Weyl semimetal is a new state of matter that hosts Weyl fermions as emergent quasiparticles and admits a topological classification that protects Fermi arc surface states on the boundary of a bulk sample. This unusual electronic structure has deep analogies with particle physics and leads to unique topological properties. We report the experimental discovery of a Weyl semimetal, tantalum arsenide (TaAs). Using photoemission spectroscopy, we directly observe Fermi arcs on the surface, as well as the Weyl fermion cones and Weyl nodes in the bulk of TaAs single crystals. We find that Fermi arcs terminate on the Weyl fermion nodes, consistent with their topological character. Our work opens the field for the experimental study of Weyl fermions in physics and materials science.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.