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Advances in Condensed Matter Physics
Volume 2015, Article ID 419017, 5 pages
http://dx.doi.org/10.1155/2015/419017
Research Article

Gap Structure of the Overdoped Iron-Pnictide Superconductor Ba(Fe0.942Ni0.058)2As2: A Low-Temperature Specific-Heat Study

1State Key Laboratory of Functional Materials for Informatics and Shanghai Center for Superconductivity, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
2Department of Physics, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
3World Premier International Research Center, Tohoku University, Sendai 980-8578, Japan

Received 15 December 2014; Accepted 11 March 2015

Academic Editor: Jörg Fink

Copyright © 2015 Gang Mu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

  1. G. Mu, Y. Wang, L. Shan, and H.-H. Wen, “Possible nodeless superconductivity in the noncentrosymmetric superconductor Mg12-δ Ir19 B16,” Physical Review B, vol. 76, no. 6, Article ID 064527, 2007. View at Publisher · View at Google Scholar · View at Scopus
  2. F. Bouquet, R. A. Fisher, N. E. Phillips, D. G. Hinks, and J. D. Jorgensen, “Specific heat of Mg11B2: evidence for a second energy gap,” Physical Review Letters, vol. 87, no. 4, Article ID 047001, 2001. View at Google Scholar · View at Scopus
  3. H.-H. Wen, Z.-Y. Liu, F. Zhou et al., “Electronic specific heat and low-energy quasiparticle excitations in the superconducting state of La2−xSrxCuO4 single crystals,” Physical Review B, vol. 70, no. 21, Article ID 214505, 2004. View at Publisher · View at Google Scholar · View at Scopus
  4. P. J. Hirschfeld, M. M. Korshunov, and I. I. Mazin, “Gap symmetry and structure of Fe-based superconductors,” Reports on Progress in Physics, vol. 74, no. 12, Article ID 124508, 2011. View at Publisher · View at Google Scholar · View at Scopus
  5. I. I. Mazin, D. J. Singh, M. D. Johannes, and M. H. Du, “Unconventional superconductivity with a sign reversal in the order parameter of LaFeAsO1-xFx,” Physical Review Letters, vol. 101, no. 5, Article ID 057003, 2008. View at Publisher · View at Google Scholar · View at Scopus
  6. K. Kuroki, S. Onari, R. Arita et al., “Erratum: unconventional pairing originating from the disconnected fermi surfaces of superconducting LaFeAsO1-xFx,” Physical Review Letters, vol. 102, no. 10, Article ID 109902, 2009. View at Publisher · View at Google Scholar · View at Scopus
  7. D. Mou, S. Liu, X. Jia et al., “Distinct Fermi surface topology and nodeless superconducting gap in a (Tl0.58Rb0.42)Fe1.72Se2 superconductor,” Physical Review Letters, vol. 106, no. 10, Article ID 107001, 2011. View at Publisher · View at Google Scholar · View at Scopus
  8. J. D. Fletcher, A. Serafin, L. Malone et al., “Evidence for a nodal-line superconducting state in LaFePO,” Physical Review Letters, vol. 102, no. 14, Article ID 147001, 2009. View at Publisher · View at Google Scholar · View at Scopus
  9. J. K. Dong, S. Y. Zhou, T. Y. Guan et al., “Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2,” Physical Review Letters, vol. 104, no. 8, Article ID 087005, 2010. View at Publisher · View at Google Scholar · View at Scopus
  10. Y. Zhang, Z. R. Ye, Q. Q. Ge et al., “Nodal superconducting-gap structure in ferropnictide superconductor BaFe2(As0.7P0.3)2,” Nature Physics, vol. 8, no. 5, pp. 371–375, 2012. View at Publisher · View at Google Scholar · View at Scopus
  11. Y.-L. Wang, L. Shan, L. Fang, P. Cheng, C. Ren, and H.-H. Wen, “Multiple gaps in SmFeAsO0.9F0.1 revealed by point-contact spectroscopy,” Superconductor Science and Technology, vol. 22, no. 1, Article ID 015018, 2009. View at Publisher · View at Google Scholar · View at Scopus
  12. T. Sato, S. Souma, K. Nakayama et al., “Superconducting gap and pseudogap in iron-based layered superconductor La(O1−xFx)FeAs,” Journal of the Physical Society of Japan, vol. 77, no. 6, Article ID 063708, 2008. View at Publisher · View at Google Scholar · View at Scopus
  13. S. Kawasaki, K. Shimada, G. F. Chen, J. L. Luo, N. L. Wang, and G.-Q. Zheng, “Two superconducting gaps in LaFeAsO0.92F0.08 revealed by 75As nuclear quadrupole resonance,” Physical Review B, vol. 78, no. 22, Article ID 220506, 2008. View at Publisher · View at Google Scholar · View at Scopus
  14. G. Mu, X. Zhu, L. Fang et al., “Nodal gap in Fe-based layered superconductor LaO0:9F0.1−δFeAs probed by specific heat measurements,” Chinese Physics Letters, vol. 25, pp. 2221–2224, 2008. View at Google Scholar
  15. T. Y. Chen, Z. Tesanovic, R. H. Liu, X. H. Chen, and C. L. Chien, “A BCS-like gap in the superconductor SmFeAsO0.85F0.15,” Nature, vol. 453, no. 7199, pp. 1224–1227, 2008. View at Publisher · View at Google Scholar · View at Scopus
  16. H. Ding, P. Richard, K. Nakayama et al., “Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2,” Europhysics Letters, vol. 83, no. 4, Article ID 47001, 2008. View at Publisher · View at Google Scholar · View at Scopus
  17. K. Hashimoto, T. Shibauchi, T. Kato et al., “Microwave penetration depth and quasiparticle conductivity of PrFeAsO1-y single crystals: evidence for a full-gap superconductor,” Physical Review Letters, vol. 102, no. 1, Article ID 017002, 2009. View at Publisher · View at Google Scholar · View at Scopus
  18. G. Mu, H. Luo, Z. Wang, L. Shan, C. Ren, and H.-H. Wen, “Low temperature specific heat of the hole-doped Ba0.6K0.4Fe2As2 single crystals,” Physical Review B: Condensed Matter and Materials Physics, vol. 79, no. 17, Article ID 174501, 2009. View at Publisher · View at Google Scholar · View at Scopus
  19. J.-P. Reid, M. A. Tanatar, X. G. Luo et al., “Nodes in the gap structure of the iron arsenide superconductor Ba(Fe1-xCox)2As2 from c -axis heat transport measurements,” Physical Review B—Condensed Matter and Materials Physics, vol. 82, Article ID 064501, 2010. View at Publisher · View at Google Scholar · View at Scopus
  20. B. Zeng, G. Mu, H. Q. Luo et al., “Anisotropic structure of the order parameter in FeSe0.45Te0.55 revealed by angle-resolved specific heat,” Nature Communications, vol. 1, no. 8, article 112, 2010. View at Publisher · View at Google Scholar · View at Scopus
  21. C. Martin, H. Kim, R. T. Gordon et al., “Evidence from anisotropic penetration depth for a three-dimensional nodal superconducting gap in single-crystalline Ba (Fe1–x Nix) 2As2,” Physical Review B—Condensed Matter and Materials Physics, vol. 81, no. 6, Article ID 060505, 2010. View at Publisher · View at Google Scholar · View at Scopus
  22. J.-P. Reid, M. A. Tanatar, X. G. Luo et al., “Nodes in the gap structure of the iron arsenide superconductor Ba(Fe1-xCox)2As2 from c-axis heat transport measurements,” Physical Review B: Condensed Matter and Materials Physics, vol. 82, no. 6, Article ID 064501, 2010. View at Publisher · View at Google Scholar · View at Scopus
  23. K. Gofryk, A. B. Vorontsov, I. Vekhter et al., “Effect of annealing on the specific heat of Ba(Fe1−xCox)2As2,” Physical Review B, vol. 83, no. 6, Article ID 064513, 2011. View at Publisher · View at Google Scholar · View at Scopus
  24. T. Fischer, A. V. Pronin, J. Wosnitza et al., “Highly anisotropic energy gap in superconducting Ba (Fe0.9Co0.1)2As2 from optical conductivity measurements,” Physical Review B, vol. 82, no. 22, Article ID 224507, 2010. View at Publisher · View at Google Scholar · View at Scopus
  25. G. Mu, J. Tang, Y. Tanabe, J. Xu, S. Heguri, and K. Tanigaki, “Evidence for line nodes in the energy gap of the overdoped BaFe1-xCox2As2 from low-temperature specific heat measurements,” Physical Review B: Condensed Matter and Materials Physics, vol. 84, no. 5, Article ID 054505, 2011. View at Publisher · View at Google Scholar · View at Scopus
  26. G. Mu, J. Tang, Y. Tanabe et al., “A field-directional specific heat study on the gap structure of overdoped Ba(Fe1-xCox)2As2,” Journal of the Physical Society of Japan, vol. 82, no. 5, Article ID 054714, 2013. View at Publisher · View at Google Scholar · View at Scopus
  27. M. Sigrist and K. Ueda, “Phenomenological theory of unconventional superconductivity,” Reviews of Modern Physics, vol. 63, no. 2, pp. 239–311, 1991. View at Publisher · View at Google Scholar · View at Scopus
  28. N. E. Hussey, “Low-energy quasiparticles in high-Tc cuprates,” Advances in Physics, vol. 51, no. 8, pp. 1685–1771, 2002. View at Publisher · View at Google Scholar · View at Scopus
  29. P. Popovich, A. V. Boris, O. V. Dolgov et al., “Specific heat measurements of Ba0.68K0.32Fe2As2 single crystals: evidence for a multiband strong-coupling superconducting state,” Physical Review Letters, vol. 105, no. 2, Article ID 027003, 2010. View at Publisher · View at Google Scholar · View at Scopus
  30. K. Gofryk, A. S. Sefat, M. A. McGuire et al., “Doping-dependent specific heat study of the superconducting gap in Ba(Fe1-x Cox)2As2,” Physical Review B, vol. 81, no. 18, Article ID 184518, 2010. View at Publisher · View at Google Scholar · View at Scopus
  31. L. Fang, H. Luo, P. Cheng et al., “Roles of multiband effects and electron-hole asymmetry in the superconductivity and normal-state properties of Ba(Fe1-xCox)2As2,” Physical Review B, vol. 80, no. 14, Article ID 140508, 2009. View at Publisher · View at Google Scholar · View at Scopus
  32. N. Ni, A. Thaler, J. Q. Yan et al., “Temperature versus doping phase diagrams for Ba(Fe1−xTMx)2As2(TM = Ni,Cu,Cu/Co) single crystals,” Physical Review B, vol. 82, Article ID 024519, 2010. View at Publisher · View at Google Scholar
  33. G. Mu, B. Zeng, P. Cheng et al., “Sizable residual quasiparticle density of states induced by impurity scattering effect in Ba(Fe1-xCox)2As2 single crystals,” Chinese Physics Letters, vol. 27, no. 3, Article ID 037402, 2010. View at Publisher · View at Google Scholar · View at Scopus