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Peer-reviewed Last author Corresponding author Open access
Nov 6, 2019

Superconducting properties of (NH<inf>3</inf>) <inf>y</inf> Li <inf>x</inf> FeSe<inf>0.5</inf>Te<inf>0.5</inf> under pressure

New Journal of Physics
  • Xiaofan Yang
  • Tong He
  • Tomoya Taguchi
  • Huan Li
  • Yanan Wang
  • Hidenori Goto
  • Ritsuko Eguchi
  • Takafumi Miyazaki
  • Hitoshi Yamaoka
  • Hirofumi Ishii
  • Yen Fa Liao
  • Yoshihiro Kubozono
  • Display all

Volume
21
Number
11
First page
113010
Last page
Language
English
Publishing type
Research paper (scientific journal)
DOI
10.1088/1367-2630/ab5034

© 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft. We prepared two superconducting phases of (NH3) y Li x FeSe0.5Te0.5, which show superconducting transition temperatures (T c's) as high as 20.2 and 29.5 K at ambient pressure, here called the 'low-T c phase' and 'high-T c phase'. The temperature dependence of electrical resistance (R) was measured for the low-T c phase of (NH3) y Li x FeSe0.5Te0.5 over a pressure (p) range of 0-14 GPa, and for the high-T c phase of (NH3) y Li x FeSe0.5Te0.5 over 0-19 GPa, yielding double-dome superconducting T c-p phase diagrams, i.e. two superconducting phases (SC-I and SC-II) were found for both the low-T c and high-T c phases under pressure. For the low-T c phase, the maximum T c was 20.2 K at 0 GPa for SC-I, and 19.9 K at 8.98 GPa for SC-II. For the high-T c phase, the maximum T c was 33.0 K at 1.00 GPa for SC-I, and 24.0 K at 11.5-13.2 GPa for SC-II. These results imply that the maximum T c value of the high pressure phase (SC-II) does not exceed the maximum value of the SC-I, unlike what was shown in the T c-p phase diagrams of (NH3) y Li x FeSe and (NH3) y Cs x FeSe investigated previously. Nevertheless, the double-dome T c-p phase diagram was found in metal-doped FeSe0.5Te0.5, indicating that this feature is universal in metal-doped FeSe1-zTe z . Moreover, no structural phase transitions were observed for either the low-T c or high-T c phases of (NH3) y Li x FeSe0.5Te0.5 over the wide pressure range of 0-15.3 GPa, and the T c-lattice constant (c) plots for both phases were recorded to determine the critical point separating SC-I and SC-II.

Link information
DOI
https://doi.org/10.1088/1367-2630/ab5034
Scopus
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85075777237&origin=inward Open access
Scopus Citedby
https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85075777237&origin=inward
ID information
  • DOI : 10.1088/1367-2630/ab5034
  • ISSN : 1367-2630
  • SCOPUS ID : 85075777237

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