### Topological nodal-line fermions in spin-orbit metal PbTaSe2

Here we discuss how topological semimetals can support one-dimensional Fermi lines or zero-dimensional Weyl points in momentum space, where the valence and conduction bands touch. While the degeneracy points in Weyl semimetals are robust against any perturbation that preserves translational symmetry, nodal lines require protection by additional crystalline symmetries such as mirror reflection. Here we report, based on a systematic theoretical study and a detailed experimental characterization, the existence of topological nodal-line states in the non-centrosymmetric compound PbTaSe

_{2}with strong spin-orbit coupling. Remarkably, the spin-orbit nodal lines in PbTaSe_{2}are not only protected by the reflection symmetry but also characterized by an integer topological invariant. Our detailed angle-resolved photoemission measurements, first-principles simulations and theoretical topological analysis illustrate the physical mechanism underlying the formation of the topological nodal-line states and associated surface states for the first time, thus paving the way towards exploring the exotic properties of the topological nodal-line fermions in condensed matter systems.- Authors:
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »

- Publication Date:

- Grant/Contract Number:
- FG02-07ER46352

- Type:
- Accepted Manuscript

- Journal Name:
- Nature Communications

- Additional Journal Information:
- Journal Volume: 7; Journal ID: ISSN 2041-1723

- Publisher:
- Nature Publishing Group

- Research Org:
- Northeastern Univ., Boston, MA (United States)

- Sponsoring Org:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 36 MATERIALS SCIENCE

- OSTI Identifier:
- 1311503

```
Bian, Guang, Chang, Tay-Rong, Sankar, Raman, Xu, Su-Yang, Zheng, Hao, Neupert, Titus, Chiu, Ching-Kai, Huang, Shin-Ming, Chang, Guoqing, Belopolski, Ilya, Sanchez, Daniel S., Neupane, Madhab, Alidoust, Nasser, Liu, Chang, Wang, BaoKai, Lee, Chi-Cheng, Jeng, Horng-Tay, Zhang, Chenglong, Yuan, Zhujun, Jia, Shuang, Bansil, Arun, Chou, Fangcheng, Lin, Hsin, and Hasan, M. Zahid.
```*Topological nodal-line fermions in spin-orbit metal PbTaSe2*. United States: N. p.,
Web. doi:10.1038/ncomms10556.

```
Bian, Guang, Chang, Tay-Rong, Sankar, Raman, Xu, Su-Yang, Zheng, Hao, Neupert, Titus, Chiu, Ching-Kai, Huang, Shin-Ming, Chang, Guoqing, Belopolski, Ilya, Sanchez, Daniel S., Neupane, Madhab, Alidoust, Nasser, Liu, Chang, Wang, BaoKai, Lee, Chi-Cheng, Jeng, Horng-Tay, Zhang, Chenglong, Yuan, Zhujun, Jia, Shuang, Bansil, Arun, Chou, Fangcheng, Lin, Hsin, & Hasan, M. Zahid.
```*Topological nodal-line fermions in spin-orbit metal PbTaSe2*. United States. doi:10.1038/ncomms10556.

```
Bian, Guang, Chang, Tay-Rong, Sankar, Raman, Xu, Su-Yang, Zheng, Hao, Neupert, Titus, Chiu, Ching-Kai, Huang, Shin-Ming, Chang, Guoqing, Belopolski, Ilya, Sanchez, Daniel S., Neupane, Madhab, Alidoust, Nasser, Liu, Chang, Wang, BaoKai, Lee, Chi-Cheng, Jeng, Horng-Tay, Zhang, Chenglong, Yuan, Zhujun, Jia, Shuang, Bansil, Arun, Chou, Fangcheng, Lin, Hsin, and Hasan, M. Zahid. 2016.
"Topological nodal-line fermions in spin-orbit metal PbTaSe2". United States.
doi:10.1038/ncomms10556. https://www.osti.gov/servlets/purl/1311503.
```

```
@article{osti_1311503,
```

title = {Topological nodal-line fermions in spin-orbit metal PbTaSe2},

author = {Bian, Guang and Chang, Tay-Rong and Sankar, Raman and Xu, Su-Yang and Zheng, Hao and Neupert, Titus and Chiu, Ching-Kai and Huang, Shin-Ming and Chang, Guoqing and Belopolski, Ilya and Sanchez, Daniel S. and Neupane, Madhab and Alidoust, Nasser and Liu, Chang and Wang, BaoKai and Lee, Chi-Cheng and Jeng, Horng-Tay and Zhang, Chenglong and Yuan, Zhujun and Jia, Shuang and Bansil, Arun and Chou, Fangcheng and Lin, Hsin and Hasan, M. Zahid},

abstractNote = {Here we discuss how topological semimetals can support one-dimensional Fermi lines or zero-dimensional Weyl points in momentum space, where the valence and conduction bands touch. While the degeneracy points in Weyl semimetals are robust against any perturbation that preserves translational symmetry, nodal lines require protection by additional crystalline symmetries such as mirror reflection. Here we report, based on a systematic theoretical study and a detailed experimental characterization, the existence of topological nodal-line states in the non-centrosymmetric compound PbTaSe2 with strong spin-orbit coupling. Remarkably, the spin-orbit nodal lines in PbTaSe2 are not only protected by the reflection symmetry but also characterized by an integer topological invariant. Our detailed angle-resolved photoemission measurements, first-principles simulations and theoretical topological analysis illustrate the physical mechanism underlying the formation of the topological nodal-line states and associated surface states for the first time, thus paving the way towards exploring the exotic properties of the topological nodal-line fermions in condensed matter systems.},

doi = {10.1038/ncomms10556},

journal = {Nature Communications},

number = ,

volume = 7,

place = {United States},

year = {2016},

month = {2}

}