# Single Crystal Growth, Resistivity, and Electronic Structure of the Weyl Semimetals NbP and TaP

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Experimental Details

## 3. Results and Discussion

#### 3.1. Crystal Chemistry

#### 3.2. Resistivity

#### 3.3. Electronic Structure Calculations

## 4. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

- Weyl, H. Elektron und Gravitation. I. Zeitschrift für Physik A Hadrons and Nuclei
**1929**, 56, 330–352. [Google Scholar] [CrossRef] - Wan, X.; Turner, A.M.; Vishwanath, A.; Savrasov, S.Y. Topological semimetal and Fermi-arc surface states in the electronic structure of pyrochlore iridates. Phys. Rev. B
**2011**, 83, 205101. [Google Scholar] [CrossRef] - Wilczek, F. Why are there analogies between condensed matter and particle theory? Phys. Today
**1998**, 51, 11–13. [Google Scholar] [CrossRef] - Xu, S.Y.; Belopolski, I.; Sanchez, D.S.; Zhang, C.; Chang, G.; Guo, C.; Bian, G.; Yuan, Z.; Lu, H.; Chang, T.-R.; et al. Experimental discovery of a topological Weyl semimetal state in TaP. Sci. Adv.
**2015**, 1, e1501092. [Google Scholar] [CrossRef] [PubMed] - Liu, Z.K.; Yang, L.X.; Sun, Y.; Zhang, T.; Peng, H.; Yang, H.F.; Chen, C.; Zhang, Y.; Guo, Y.F.; Prabhakaran, D.; et al. Evolution of the Fermi surface of Weyl semimetals in the transition metal pnictide family. Nat. Mater.
**2016**, 15, 27–31. [Google Scholar] [CrossRef] [PubMed] - Xu, S.-Y.; Belopolski, I.; Alidoust, N.; Neupane, M.; Bian, G.; Zhang, C.; Sankar, R.; Chang, G.; Yuan, Z.; Lee, C.-C. Discovery of a Weyl fermion semimetal and topological Fermi arcs. Science
**2015**, 349, 613–617. [Google Scholar] [CrossRef] [PubMed] - Xu, S.-Y.; Alidoust, N.; Belopolski, I.; Yuan, Z.; Bian, G.; Chang, T.-R.; Zheng, H.; Strocov, V.-N.; Sanchez, D.-S.; Chang, G. Discovery of a Weyl fermion state with Fermi arcs in niobium arsenide. Nat. Phys.
**2015**, 11, 748–754. [Google Scholar] [CrossRef] - Lv, B.-Q.; Weng, H.-M.; Fu, B.-B.; Wang, X.-P.; Miao, H.; Ma, J.; Richard, P.; Huang, X.-C.; Zhao, L.-X.; Chen, G.F.; et al. Experimental Discovery of Weyl Semimetal TaAs. Phys. Rev. X
**2015**, 5, 031013. [Google Scholar] [CrossRef] - Zhang, C.; Yuan, Z.; Xu, S.; Lin, Z.; Tong, B.; Hasan, M.Z.; Wang, J.C.; Zhang, C.; Jia, S. Tantalum Monoarsenide: An Exotic Compensated Semimetal. arXiv, 2015; arXiv:1502.00251. [Google Scholar]
- Shekhar, C.; Nayak, A.K.; Sun, Y.; Schmidt, M.; Nicklas, M.; Leermakers, I.; Zeitler, U.; Skourski, Y.; Wosnitza, J.; Liu, Z.; et al. Extremely large magnetoresistance and ultrahigh mobility in the topological Weyl semimetal candidate NbP. Nat. Phys.
**2015**, 11. [Google Scholar] [CrossRef] - Ghimire, N. J.; Luo, Y.; Neupane, M.; Williams, D.; Bauer, E.; Ronning, F. Magnetotransport of single crystalline NbAs. J. Phys. Condens. Matter.
**2015**, 27, 152201. [Google Scholar] [CrossRef] [PubMed] - Xu, J.; Greenblatt, M.; Emge, T.; Höhn, P.; Hughbanks, T.; Tian, Y. Crystal Structure, Electrical Transport, and Magnetic Properties of Niobium Monophosphide. Inorg. Chem.
**1996**, 35, 845–849. [Google Scholar] [CrossRef] [PubMed] - Xu, D.-F.; Du, Y.-P.; Wang, Z.; Li, Y.-P.; Niu, X.-H.; Yao, Q.; Dudin, P.; Xu, Z.-A.; Wan, X.-G.; Feng, D.-L. Observation of Fermi Arcs in Non-Centrosymmetric Weyl Semi-Metal Candidate NbP. Chin. Phys. Lett.
**2015**, 32, 107101. [Google Scholar] [CrossRef] - Wang, Z.; Zheng, Y.; Shen, Z.; Lu, Y.; Fang, H.; Sheng, F.; Zhou, Y.; Yang, X.; Li, Y.; Feng, C.; Xu, Z.-A. Helicity-protected ultrahigh mobility Weyl fermions in NbP. Phys. Rev. B
**2016**, 93, 121112. [Google Scholar] [CrossRef] - Binnewies, M.; Glaum, R.; Schmidt, M.; Schmidt, P. Chemical Vapor Transport Reactions; Walter de Gruyter: Berlin, Germany, 2012. [Google Scholar]
- Blaha, P.; Schwarz, K.; Madsen, G.; Kvasnicka, D.; Luitz, J. WIEN2k: An Augmented Plane Wave+ Local Orbitals Program for Calculating Crystal Properties; Vienna University of Technology: Vienna, Austria, 2001. [Google Scholar]
- Weng, H.; Fang, C.; Fang, Z.; Bernevig, B.A.; Dai, X. Weyl Semimetal Phase in Noncentrosymmetric Transition-Metal Monophosphides. Phys. Rev. X
**2015**, 5, 011029. [Google Scholar] [CrossRef] - Perdew, J.-P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett.
**1996**, 77, 011029. [Google Scholar] [CrossRef] [PubMed] - Sun, Y.; Wu, S.-C.; Yan, B. Topological surface states and Fermi arcs of the noncentrosymmetric Weyl semimetals TaAs, TaP, NbAs, and NbP. Phys. Rev. B
**2015**, 92, 115428. [Google Scholar] [CrossRef] - Huang, S.-M.; Xu, S.-Y.; Belopolski, I.; Lee, C.-C.; Chang, G.; Wang, B.; Alidoust, N.; Bian, G.; Neupane, M.; Bansil, A.; et al. Theoretical Discovery/Prediction: Weyl Semimetal states in the TaAs material (TaAs, NbAs, NbP, TaP) class. arXiv, 2015; arXiv:1501.00755. [Google Scholar]
- Belopolski, I.; Xu, S.-Y.; Sanchez, D.; Chang, G.; Guo, C.; Neupane, M.; Zheng, H.; Lee, C.-C.; Huang, S.-M.; Bian, G.; et al. Observation of surface states derived from topological Fermi arcs in the Weyl semimetal NbP. arXiv, 2015; arXiv:1509.07465. [Google Scholar]

**Figure 1.**Conventional unit cell of NbP or TaP (

**a**); Trigonal prismatic environment of P (

**b**) and Nb/Ta (

**c**).

**Figure 3.**Resistivity vs. temperature of an unoriented crystal of NbP. Single crystals of NbP are shown in the inset.

**Figure 4.**Resistivity vs. temperature of an unoriented crystal of TaP. Single crystals of TaP are shown in the inset.

**Figure 6.**The band structure of NbP. The left panel does not include spin orbit coupling (SOC); the right panel includes SOC.

**Figure 7.**The band structure of TaP. The left panel does not include SOC; the right panel includes SOC.

© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Sapkota, D.; Mukherjee, R.; Mandrus, D.
Single Crystal Growth, Resistivity, and Electronic Structure of the Weyl Semimetals NbP and TaP. *Crystals* **2016**, *6*, 160.
https://doi.org/10.3390/cryst6120160

**AMA Style**

Sapkota D, Mukherjee R, Mandrus D.
Single Crystal Growth, Resistivity, and Electronic Structure of the Weyl Semimetals NbP and TaP. *Crystals*. 2016; 6(12):160.
https://doi.org/10.3390/cryst6120160

**Chicago/Turabian Style**

Sapkota, Deepak, Rupam Mukherjee, and David Mandrus.
2016. "Single Crystal Growth, Resistivity, and Electronic Structure of the Weyl Semimetals NbP and TaP" *Crystals* 6, no. 12: 160.
https://doi.org/10.3390/cryst6120160