Title: Spin Polarization and Texture of the Fermi Arcs in the Weyl Fermion Semimetal TaAs

Abstract

A Weyl semimetal is a new state of matter that hosts Weyl fermions as quasiparticle excitations. The Weyl fermions at zero energy correspond to points of bulk-band degeneracy, called Weyl nodes, which are separated in momentum space and are connected only through the crystal’s boundary by an exotic Fermi arc surface state. Here, we experimentally measure the spin polarization of the Fermi arcs in the first experimentally discovered Weyl semimetal TaAs. Our spin data, for the first time, reveal that the Fermi arcs’ spin-polarization magnitude is as large as 80% and lies completely in the plane of the surface. Moreover, we demonstrate that the chirality of the Weyl nodes in TaAs cannot be inferred by the spin texture of the Fermi arcs. The observed nondegenerate property of the Fermi arcs is important for establishing its exact topological nature, which reveals that spins on the arc form a novel type of 2D matter. In addition, the nearly full spin polarization we observed (~80%) may be useful in spintronic applications.

Authors:

Xu, Su-Yang ^[1]; Belopolski, Ilya ^[1]; Sanchez, Daniel S. ^[1]; Neupane, Madhab ^[2]; Chang, Guoqing ^[3]; Yaji, Koichiro ^[4]; Yuan, Zhujun ^[5]; Zhang, Chenglong ^[5]; Kuroda, Kenta ^[4]; Bian, Guang ^[1]; Guo, Cheng ^[5]; Lu, Hong ^[5]; Chang, Tay-Rong ^[6]; Alidoust, Nasser ^[1]; Zheng, Hao ^[1]; Lee, Chi-Cheng ^[3]; Huang, Shin-Ming ^[3]; Hsu, Chuang-Han ^[3]; Jeng, Horng-Tay ^[7]; Bansil, Arun ^[8] more »; Neupert, Titus ^[9]; Komori, Fumio ^[4]; Kondo, Takeshi ^[4]; Shin, Shik ^[4]; Lin, Hsin ^[3]; Jia, Shuang ^[10]; Hasan, M. Zahid ^[1] « less

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+ Show Author Affiliations

1. Princeton Univ., NJ (United States). Dept. of Physics, Lab. for Topological Quantum Matter and Spectroscopy
2. Princeton Univ., NJ (United States). Dept. of Physics, Lab. for Topological Quantum Matter and Spectroscopy; Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Condensed Matter and Magnet Science Group; Univ. of Central Florida, Orlando, FL (United States). Dept. of Physics
3. Centre for Advanced 2D Materials and Graphene Research Centre National Univ. of Singapore (Singapore); National Univ. of Singapore (Singapore). Dept. of Physics
4. Univ of Tokyo, Chiba (Japan). Inst. for Solid State Physics (ISSP)
5. Peking Univ., Beijing (China). International Center for Quantum Materials, School of Physics
6. National Tsing Hua Univ., Hsinchu (Taiwan). Dept. of Physics
7. National Tsing Hua Univ., Hsinchu (Taiwan). Dept. of Physics; Academia Sinica, Taipei (Taiwan). Inst. of Physics
8. Northeastern Univ., Boston, MA (United States). Dept. of Physics
9. Princeton Univ., NJ (United States). Joseph Henry lab., Dept. of Physics
10. Peking Univ., Beijing (China). International Center for Quantum Materials, School of Physics; Collaborative Innovation Center of Quantum Matter, Beijing (China)

Publication Date:

Tue Mar 01 00:00:00 EST 2016

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR)

OSTI Identifier:

1414083

Alternate Identifier(s):

OSTI ID: 1239862

Report Number(s):

LA-UR-15-28623
Journal ID: ISSN 0031-9007; PRLTAO; TRN: US1800618

Grant/Contract Number:  

AC52-06NA25396; FG02-07ER46352; AC02-05CH11231; FG-02-05ER46200

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Physical Review Letters

Additional Journal Information:

Journal Volume: 116; Journal Issue: 9; Journal ID: ISSN 0031-9007

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY