Discovery of a Weyl fermion state with Fermi arcs in niobium arsenide

DOI: 10.1038/nphys3437

Authors: Su-Yang Xu (Princeton University) , Nasser Alidoust (Princeton University) , Ilya Belopolski (Princeton University) , Zhujun Yuan (Peking University) , Guang Bian (Princeton University) , Tay-Rong Chang (Princeton University) , Hao Zheng (Princeton University) , Vladimir N. Strocov (Paul Scherrer Institute) , Daniel Sanchez (Princeton University) , Guoqing Chang (National University of Singapore) , Chenglong Zhang (Peking University) , Daixiang Mou (US DOE Ames) , Yun Wu (US DOE Ames) , Lunan Huang (US DOE Ames) , Chi-Cheng Lee (National University of Singapore) , Shin-Ming Huang (National University of Singapore) , Baokai Wang (National University of Singapore) , Arun Bansil (Northeastern University) , Horng-Tay Jeng (National Tsing Hua University) , Titus Neupert (Princeton University) , Adam Kaminski (US DOE Ames) , Hsin Lin (National University of Singapore) , Shuang Jia (Peking University; Collaborative Innovation Center of Quantum Matter (China)) , M. Zahid Hasan (Princeton University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature Physics , VOL 11 , PAGES 748 - 754

State: Published (Approved)
Published: August 2015
Diamond Proposal Number(s): 10074

Abstract: Three types of fermions play a fundamental role in our understanding of nature: Dirac, Majorana and Weyl. Whereas Dirac fermions have been known for decades, the latter two have not been observed as any fundamental particle in high-energy physics, and have emerged as a much-sought-out treasure in condensed matter physics. A Weyl semimetal is a novel crystal whose low-energy electronic excitations behave as Weyl fermions. It has received worldwide interest and is believed to open the next era of condensed matter physics after graphene and three-dimensional topological insulators. However, experimental research has been held back because Weyl semimetals are extremely rare in nature. Here, we present the experimental discovery of the Weyl semimetal state in an inversion-symmetry-breaking single-crystalline solid, niobium arsenide (NbAs). Utilizing the combination of soft X-ray and ultraviolet photoemission spectroscopy, we systematically study both the surface and bulk electronic structure of NbAs. We experimentally observe both the Weyl cones in the bulk and the Fermi arcs on the surface of this system. Our ARPES data, in agreement with our theoretical band structure calculations, identify the Weyl semimetal state in NbAs, which provides a real platform to test the potential of Weyltronics.

Journal Keywords: Topological insulators

Subject Areas: Physics, Materials


Instruments: I05-ARPES

Other Facilities: 4.0.3, 10.0.1, 12.0.1 at Advanced Light Source (ALS); 5-4 at Stanford Synchrotron Radiation Lightsource (SSRL)

Added On: 19/02/2016 12:01

Discipline Tags:

Quantum Materials Physics Hard condensed matter - structures Materials Science

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES)