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Title: A strongly robust type II Weyl fermion semimetal state in Ta 3S 2

Weyl semimetals are of great interest because they provide the first realization of the Weyl fermion, exhibit exotic quantum anomalies, and host Fermi arc surface states. The separation between Weyl nodes of opposite chirality gives a measure of the robustness of the Weyl semimetal state. To exploit the novel phenomena that arise from Weyl fermions in applications, it is crucially important to find robust separated Weyl nodes. Here, we propose a methodology to design robust Weyl semimetals with well-separated Weyl nodes. Using this methodology as a guideline, we search among the material parameter space and identify by far the most robust and ideal Weyl semimetal candidate in the single-crystalline compound tantalum sulfide (Ta 3S 2) with new and novel properties beyond TaAs. Crucially, our results show that Ta 3S 2 has the largest k-space separation between Weyl nodes among known Weyl semimetal candidates, which is about twice larger than the measured value in TaAs and 20 times larger than the predicted value in WTe 2. Moreover, all Weyl nodes in Ta 3S 2 are of type II. Therefore, Ta 3S 2 is a type II Weyl semimetal. Furthermore, we predict that increasing the lattice by <4% can annihilate all Weylmore » nodes, driving a novel topological metal-to-insulator transition from a Weyl semimetal state to a topological insulator state. The robust type II Weyl semimetal state and the topological metal-to-insulator transition in Ta 3S 2 are potentially useful in device applications. Our methodology can be generally applied to search for new Weyl semimetals.« less
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [1] ;  [3] ;  [2] ;  [2] ;  [2] ;  [2] ;  [4] ;  [5] ;  [1] ;  [2]
  1. National Univ. of Singapore (Singapore). Center for Advanced 2D Materials and Graphene Research Center and Dept. of Physics
  2. Princeton Univ., NJ (United States). Lab. for Topological Quantum Matter and Spectroscopy and Dept. of Physics
  3. Princeton Univ., NJ (United States). Lab. for Topological Quantum Matter and Spectroscopy and Dept. of Physics; National Tsing Hua Univ., Hsinchu (Taiwan). Dept. of Physics
  4. National Tsing Hua Univ., Hsinchu (Taiwan). Dept. of Physics; Academia Sinica, Taipei (Taiwan). Inst. of Physics
  5. Northeastern Univ., Boston, MA (United States). Dept. of Physics
Publication Date:
Grant/Contract Number:
FG02-07ER46352; FG-02-05ER46200; NRF-NRFF2013-03; AC02-05CH11231; GBMF4547
Type:
Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 2; Journal Issue: 6; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Research Org:
Northeastern Univ., Boston, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21); National Research Foundation of Korea (NRF); National Science Council (NSC); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); ordon and Betty Moore Foundation
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Weyl fermion; Fermi arc; Topology
OSTI Identifier:
1466571

Chang, Guoqing, Xu, Su-Yang, Sanchez, Daniel S., Huang, Shin-Ming, Lee, Chi-Cheng, Chang, Tay-Rong, Bian, Guang, Zheng, Hao, Belopolski, Ilya, Alidoust, Nasser, Jeng, Horng-Tay, Bansil, Arun, Lin, Hsin, and Hasan, M. Zahid. A strongly robust type II Weyl fermion semimetal state in Ta3S2. United States: N. p., Web. doi:10.1126/sciadv.1600295.
Chang, Guoqing, Xu, Su-Yang, Sanchez, Daniel S., Huang, Shin-Ming, Lee, Chi-Cheng, Chang, Tay-Rong, Bian, Guang, Zheng, Hao, Belopolski, Ilya, Alidoust, Nasser, Jeng, Horng-Tay, Bansil, Arun, Lin, Hsin, & Hasan, M. Zahid. A strongly robust type II Weyl fermion semimetal state in Ta3S2. United States. doi:10.1126/sciadv.1600295.
Chang, Guoqing, Xu, Su-Yang, Sanchez, Daniel S., Huang, Shin-Ming, Lee, Chi-Cheng, Chang, Tay-Rong, Bian, Guang, Zheng, Hao, Belopolski, Ilya, Alidoust, Nasser, Jeng, Horng-Tay, Bansil, Arun, Lin, Hsin, and Hasan, M. Zahid. 2016. "A strongly robust type II Weyl fermion semimetal state in Ta3S2". United States. doi:10.1126/sciadv.1600295. https://www.osti.gov/servlets/purl/1466571.
@article{osti_1466571,
title = {A strongly robust type II Weyl fermion semimetal state in Ta3S2},
author = {Chang, Guoqing and Xu, Su-Yang and Sanchez, Daniel S. and Huang, Shin-Ming and Lee, Chi-Cheng and Chang, Tay-Rong and Bian, Guang and Zheng, Hao and Belopolski, Ilya and Alidoust, Nasser and Jeng, Horng-Tay and Bansil, Arun and Lin, Hsin and Hasan, M. Zahid},
abstractNote = {Weyl semimetals are of great interest because they provide the first realization of the Weyl fermion, exhibit exotic quantum anomalies, and host Fermi arc surface states. The separation between Weyl nodes of opposite chirality gives a measure of the robustness of the Weyl semimetal state. To exploit the novel phenomena that arise from Weyl fermions in applications, it is crucially important to find robust separated Weyl nodes. Here, we propose a methodology to design robust Weyl semimetals with well-separated Weyl nodes. Using this methodology as a guideline, we search among the material parameter space and identify by far the most robust and ideal Weyl semimetal candidate in the single-crystalline compound tantalum sulfide (Ta3S2) with new and novel properties beyond TaAs. Crucially, our results show that Ta3S2 has the largest k-space separation between Weyl nodes among known Weyl semimetal candidates, which is about twice larger than the measured value in TaAs and 20 times larger than the predicted value in WTe2. Moreover, all Weyl nodes in Ta3S2 are of type II. Therefore, Ta3S2 is a type II Weyl semimetal. Furthermore, we predict that increasing the lattice by <4% can annihilate all Weyl nodes, driving a novel topological metal-to-insulator transition from a Weyl semimetal state to a topological insulator state. The robust type II Weyl semimetal state and the topological metal-to-insulator transition in Ta3S2 are potentially useful in device applications. Our methodology can be generally applied to search for new Weyl semimetals.},
doi = {10.1126/sciadv.1600295},
journal = {Science Advances},
number = 6,
volume = 2,
place = {United States},
year = {2016},
month = {6}
}