Superstructures and Superconductivity Linked with Pd Intercalation in Nb2PdxSe5

Neu, Jennifer; Graf, David; Wei, Kaya; Gaiser, Alyssa; Xin, Yan; Lai, You; Albrecht-Schmitt, Thomas E.; Baumbach, Ryan; Singh, David J.; Siegrist, Theo

doi:10.1021/acs.chemmater.0c02291

Superstructures and Superconductivity Linked with Pd Intercalation in Nb₂Pd_xSe₅

Journal Article · Wed Sep 02 00:00:00 EDT 2020 · Chemistry of Materials

DOI:https://doi.org/10.1021/acs.chemmater.0c02291· OSTI ID:1673296

^[1]; Graf, David ^[2]; Wei, Kaya ^[2]; Gaiser, Alyssa ^[3]; Xin, Yan ^[2]; Lai, You ^[2]; Albrecht-Schmitt, Thomas E. ^[3]; Baumbach, Ryan ^[2]; ^[4]; Siegrist, Theo ^[5]

National High Magnetic Field Laboratory, Tallahassee, FL (United States); University of Missouri
National High Magnetic Field Laboratory, Tallahassee, FL (United States)
Florida State University, Tallahassee, FL (United States)
University of Missouri, Columbia, MO (United States)
National High Magnetic Field Laboratory, Tallahassee, FL (United States); FAMU-FSU College of Engineering, Tallahassee, FL (United States)

Single crystals of Nb₂Pd_xSe₅ have been grown covering a broad range of palladium stoichiometries, from x = 0.68 to x = 0.95 (Pd2 occupancies 0.36 and 0.90 respectively). Miscibility gaps in the Pd stoichiometry range are related to superstructures resulting from staged filling and ordering of the partially filled Pd atom site (Pd2, Wyckoff site 2a). For Pd2 near 1/2 occupancy, a superstructure based on an incommensurate occupation wave with modulation along the monoclinic b-axis is identified. Here, a superconducting dome is found for Pd2 occupancies above 0.58, with maximum Tc for Pd2 occupancy of approximately 2/3. DFT calculations for the fully and 1/2 occupied Pd2 site show that Nb₂Pd_xSe₅ can be considered an intercalation compound for Pd2 occupancy above the minimum required for structural stability.

View Accepted Manuscript (DOE)

Research Organization:: University of Missouri, Columbia, MO (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

Grant/Contract Number:: SC0019114

OSTI ID:: 1673296

Journal Information:: Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 19 Vol. 32; ISSN 0897-4756

Publisher:: American Chemical Society (ACS)Copyright Statement

Country of Publication:: United States

Language:: English

References (19)

Specific Heat of Robust Nb2PdS5 Superconductor Goyal, Reena; Tiwari, Brajesh; Jha, Rajveer Journal of Superconductivity and Novel Magnetism, Vol. 28, Issue 5 https://doi.org/10.1007/s10948-015-2961-5	journal	February 2015
Superconductivity at 5.5 K in Nb2PdSe5 Compound Goyal, Reena; Gupta, Govind; Srivastava, A. K. Journal of Superconductivity and Novel Magnetism, Vol. 29, Issue 11 https://doi.org/10.1007/s10948-016-3625-9	journal	August 2016
X-ray Photoelectron Spectroscopy, Magnetotransport and Magnetisation Study of Nb2PdS5 Superconductor Goyal, Reena; Srivastava, A. K.; Mishra, Monu Journal of Superconductivity and Novel Magnetism, Vol. 31, Issue 4 https://doi.org/10.1007/s10948-017-4415-8	journal	December 2017
Enhanced superconductivity in hole-doped Nb2PdS5 Chen, Qian; Yang, Xiaohui; Yang, Xiaojun Frontiers of Physics, Vol. 12, Issue 5 https://doi.org/10.1007/s11467-016-0637-7	journal	December 2016
New ternary and quaternary transition-metal selenides: Syntheses and characterization Keszler, Douglas A.; Ibers, James A.; Maoyu, Shang Journal of Solid State Chemistry, Vol. 57, Issue 1, p. 68-81 https://doi.org/10.1016/S0022-4596(85)80061-X	journal	March 1985
Growth and angular dependent resistivity of Nb2Pd0.73S5.7 superconducting single crystals fiber Yadav, Anil K.; Sharma, Himanshu; Thakur, Ajay D. Materials Chemistry and Physics, Vol. 164 https://doi.org/10.1016/j.matchemphys.2015.08.019	journal	August 2015
Superconducting Fiber with Transition Temperature up to 7.43 K in Nb ₂ Pd _x S _5−δ (0.6 < x <1) Yu, Hongyan; Zuo, Ming; Zhang, Lei Journal of the American Chemical Society, Vol. 135, Issue 35 https://doi.org/10.1021/ja4062079	journal	August 2013
Erratum: CORRIGENDUM: Superconductivity with extremely large upper critical fields in Nb2Pd0.81S5 Zhang, Q.; Li, G.; Rhodes, D. Scientific Reports, Vol. 3, Issue 1 https://doi.org/10.1038/srep01682	journal	April 2013
Unconventional Andreev reflection on the quasi-one-dimensional superconductor Nb ₂ Pd _x Se ₅ Jiang, Yeping; Zhang, Xiaohang; Khim, Seunghyun AIP Advances, Vol. 6, Issue 4 https://doi.org/10.1063/1.4947298	journal	April 2016
Entropy of intercalation compounds. II. Calorimetry of electrochemical cells of the Chevrel compound Li _x Mo ₆ Se ₈ for 0⩽x⩽4 McKinnon, W. R.; Dahn, J. R.; Murray, J. J. Journal of Physics C: Solid State Physics, Vol. 19, Issue 26 https://doi.org/10.1088/0022-3719/19/26/013	journal	September 1986
Superconductivity at 2.5 K in the new transition-metal chalcogenide Ta ₂ PdSe ₅ Zhang, J.; Dong, J. K.; Xu, Y. Superconductor Science and Technology, Vol. 28, Issue 11 https://doi.org/10.1088/0953-2048/28/11/115015	journal	October 2015
Spectroscopic evidence for two-gap superconductivity in the quasi-1D chalcogenide Nb ₂ Pd _0.81 S ₅ Park, Eunsung; Lee, Sangyun; Ronning, Filip Journal of Physics: Condensed Matter, Vol. 30, Issue 16 https://doi.org/10.1088/1361-648X/aab5e5	journal	March 2018
Enhanced upper critical fields in a new quasi-one-dimensional superconductor Nb ₂ Pd _x Se ₅ Khim, Seunghyun; Lee, Bumsung; Choi, Ki-Young New Journal of Physics, Vol. 15, Issue 12 https://doi.org/10.1088/1367-2630/15/12/123031	journal	December 2013
Entropy of the intercalation compound Li x Mo 6 Se 8 from calorimetry of electrochemical cells Dahn, J. R.; McKinnon, W. R.; Murray, J. J. Physical Review B, Vol. 32, Issue 5 https://doi.org/10.1103/PhysRevB.32.3316	journal	September 1985
Anomalous metallic state and anisotropic multiband superconductivity in Nb 3 Pd 0.7 Se 7 Zhang, Q. R.; Rhodes, D.; Zeng, B. Physical Review B, Vol. 88, Issue 2 https://doi.org/10.1103/PhysRevB.88.024508	journal	July 2013
Electronic structure and upper critical field of superconducting Ta 2 PdS 5 Singh, David J. Physical Review B, Vol. 88, Issue 17 https://doi.org/10.1103/PhysRevB.88.174508	journal	November 2013
Non-Ising-like two-dimensional superconductivity in a bulk single crystal Zhang, Q. R.; Rhodes, D.; Zeng, B. Physical Review B, Vol. 94, Issue 9 https://doi.org/10.1103/PhysRevB.94.094511	journal	September 2016
Multiband Semimetallic Electronic Structure of Superconducting Ta2PdSe5 Singh, David Joseph PLOS ONE, Vol. 10, Issue 4 https://doi.org/10.1371/journal.pone.0123667	journal	April 2015
Superconductivity at 6 K and the Violation of Pauli Limit in Ta ₂ Pd _x S ₅ Lu, Yangfan; Takayama, Tomohiro; Bangura, Alimamy F. Journal of the Physical Society of Japan, Vol. 83, Issue 2 https://doi.org/10.7566/JPSJ.83.023702	journal	February 2014

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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
Crystal structure
Mathematical methods
Palladium
Superstructures
Transition metals

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Superstructures and Superconductivity Linked with Pd Intercalation in Nb2PdxSe5

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Superstructures and Superconductivity Linked with Pd Intercalation in Nb₂Pd_xSe₅