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Evidences for pressure-induced two-phase superconductivity and mixed structures of NiTe₂ and NiTe in type-II Dirac semimetal NiTe_(2-x) (x = 0.38 ± 0.09) single crystals

Feng, Z. and Si, J. and Li, T. and Dong, H. and Xu, C. and Yang, J. and Zhang, Z. and Wang, K. and Wu, H. and Hou, Q. and Xing, J.-J. and Wan, S. and Li, S. and Deng, W. and Feng, J. and Pal, A. and Chen, F. and Hu, S. and Ge, J.-Y. and Dong, C. and Wang, S. and Ren, W. and Cao, S. and Liu, Y. and Xu, X. and Zhang, J. and Chen, B. and Yeh, N.-C. (2021) Evidences for pressure-induced two-phase superconductivity and mixed structures of NiTe₂ and NiTe in type-II Dirac semimetal NiTe_(2-x) (x = 0.38 ± 0.09) single crystals. Materials Today Physics, 17 . Art. No. 100339. ISSN 2542-5293. https://resolver.caltech.edu/CaltechAUTHORS:20210119-143307326

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Abstract

Bulk NiTe₂ is a type-II Dirac semimetal with non-trivial Berry phases associated with the Dirac fermions. Theory suggests that monolayer NiTe₂ is a two-gap superconductor, whereas experimental investigation of bulk NiTe_(1.98) for pressures (P) up to 71.2 GPa do not reveal any superconductivity. Here we report experimental evidences for pressure-induced two-phase superconductivity as well as mixed structures of NiTe₂ and NiTe in Te-deficient NiTe_(2-x) (x = 0.38 ± 0.09) single crystals. Hole-dominant multi-band superconductivity with the P3¯m1 hexagonal-symmetry structure of NiTe₂ appears at P ≥ 0.5 GPa, whereas electron-dominant single-band superconductivity with the P2/m monoclinic-symmetry structure of NiTe emerges at 14.5 GPa < P < 18.4 GPa. The coexistence of hexagonal and monoclinic structures and two-phase superconductivity is accompanied by a zero Hall coefficient up to ∼ 40 GPa, and the second superconducting phase prevails above 40 GPa, reaching a maximum T_c = 7.8 K and persisting up to 52.8 GPa. Our findings suggest the critical role of Te-vacancies in the occurrence of superconductivity and potentially nontrivial topological properties in NiTe_(2-x).


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.mtphys.2020.100339DOIArticle
ORCID:
AuthorORCID
Feng, Z.0000-0001-5870-5159
Ge, J.-Y.0000-0001-5206-2930
Dong, C.0000-0002-2891-8759
Xu, X.0000-0002-3893-1148
Chen, B.0000-0002-0660-3350
Yeh, N.-C.0000-0002-1826-419X
Alternate Title:Evidences for pressure-induced two-phase superconductivity and mixed structures of NiTe2 and NiTe in type-II Dirac semimetal NiTe2-x (x = 0.38 ± 0.09) single crystals
Additional Information:© 2020 Elsevier. Received 5 December 2020, Revised 27 December 2020, Accepted 30 December 2020, Available online 18 January 2021. This work at the Shanghai University (SHU) is jointly supported by the Ministry of Science and Technology of the People’s Republic of China No. (2020YFB0704503, 2016YFB0700201, 2018YFB0704400), National Natural Science Foundation of China (11774217, 11974061, U1732162, 10904088), Shanghai Pujiang Program (13PJD015), and Science and Technology commission of Shanghai Municipality (13ZR1415200). The research at the California Institute of Technology was supported by the National Science Foundation under the Institute for Quantum Information and Matter (award #1733907). N.-C. Yeh acknowledges the hospitality and sponsorship of her visit to the SHU under the Overseas Expert Recruitment Program at SHU. The authors thank both BL15U1 and BL14B1 beamlines at the SSRF for providing the beam time, and also thank Professor Patrick A. Lee from Massachusetts Institute of Technology for stimulating discussions. Credit author statement: Zhenjie Feng, Supervision, Conceptualization, Formal analysis, Investigation, Writing – review & editing, Visualization, Project administration, Funding acquisition. Jingying Si, Tao Li, Investigation, Visualization, Formal analysis, Writing – original draft. Hongliang Dong, Ke Wang, Hao Wu, Qiang Hou, JuanJuan Xing, Shun Wan, Shujia Li, Wen Deng, Jiajia Feng, Arnab Pal, Fei Chen, Jun-Yi Ge, Shenghao Wang, Data curation, Validation. Chunqiang Xu, Yi Liu, Xiaofeng Xu, Resources. Jiong Yang, Zhou Zhang, Shunbo Hu, Formal analysis, Software, Visualization. Cheng Dong, Wei Ren, Shixun Cao, Formal analysis. Jincang Zhang, Bin Chen, Funding acquisition, Project administration. Nai-Chang Yeh, Formal analysis, Investigation, Writing – review & editing, Project administration, Funding acquisition. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Group:Institute for Quantum Information and Matter
Funders:
Funding AgencyGrant Number
Ministry of Science and Technology (China)2020YFB0704503
Ministry of Science and Technology (China)2016YFB0700201
Ministry of Science and Technology (China)2018YFB0704400
National Natural Science Foundation of China11774217
National Natural Science Foundation of China11974061
National Natural Science Foundation of ChinaU1732162
National Natural Science Foundation of China10904088
Shanghai Pujiang Program13PJD015
Science and Technology Commission of Shanghai Municipality13ZR1415200
NSFPHY-1733907
Shanghai UniversityUNSPECIFIED
Subject Keywords:NiTe_(2-x); multi-band superconductivity; single-band superconductivity; type-II Dirac semimetal
Record Number:CaltechAUTHORS:20210119-143307326
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210119-143307326
Official Citation:Z. Feng, J. Si, T. Li, H. Dong, C. Xu, J. Yang, Z. Zhang, K. Wang, H. Wu, Q. Hou, J.-J. Xing, S. Wan, S. Li, W. Deng, J. Feng, A. Pal, F. Chen, S. Hu, J.-Y. Ge, C. Dong, S. Wang, W. Ren, S. Cao, Y. Liu, X. Xu, J. Zhang, B. Chen, N.-C. Yeh, Evidences for pressure-induced two-phase superconductivity and mixed structures of NiTe2 and NiTe in type-II Dirac semimetal NiTe2-x (x = 0.38 ± 0.09) single crystals, Materials Today Physics, Volume 17, 2021, 100339, ISSN 2542-5293, https://doi.org/10.1016/j.mtphys.2020.100339. (http://www.sciencedirect.com/science/article/pii/S2542529320301632)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107557
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:20 Jan 2021 15:19
Last Modified:01 Feb 2021 23:31

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