Discovery of a Weyl fermion semimetal and topological Fermi arcs
Journal
Science
Journal Volume
349
Journal Issue
6248
Pages
613-617
Date Issued
2015
Author(s)
Xu, S. Y.
Belopolski, I.
Alidoust, N.
Neupane, M.
Bian, G.
Zhang, C.
Sankar, R.
Chang, G.
Yuan, Z.
Lee, C. C.
Huang, S. M.
Zheng, H.
Ma, J.
Sanchez, D. S.
Wang, B.
Bansil, A.
Shibayev, P. P.
Lin, H.
Jia, S.
Hasan, M. Z.
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.
Publisher
American Association for the Advancement of Science
Type
journal article