Coulomb problem in iron-based superconductors

被引:6
作者
Konig, Elio J. [1 ]
Coleman, Piers [1 ,2 ]
机构
[1] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA
[2] Royal Holloway Univ London, Dept Phys, Egham TW20 0EX, Surrey, England
关键词
TEMPERATURE; TRANSITION; SYMMETRY; FESE;
D O I
10.1103/PhysRevB.99.144522
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We discuss the role of strong Coulomb interactions in iron-based superconductors (FeSCs). The presumed s(+/-) character of these superconductors means that the condensate is not symmetry protected against Coulomb repulsion. Remarkably, the transition temperatures and the excitation gap are quite robust across the large family of iron-based superconductors, despite drastic changes in Fermi-surface geometry. The Coulomb problem is to understand how these superconductors avoid the strong on-site Coulomb interaction of the iron atoms, while maintaining a robust transition temperature. Within the dominant space of t(2g) orbitals, on-site repulsion in the FeSCs forces two linearly independent components of the condensate to vanish. This raises the possibility that iron-based superconductors might adapt their condensate to the Coulomb constraints by rotating the pairing state within the large manifold of entangled extended s-wave gap functions with different orbital and momentum space structure. We examine this "orbital and k-space flexibility" (OKF) mechanism using both Landau theory and microscopic calculations within a multiorbital t-J model. Based on our results, we conclude that OKF necessitates a large condensate degeneracy. One interesting possibility raised by our results is that a resolution to the Coulomb problem in FeSCs might require a reconsideration of triplet pairing.
引用
收藏
页数:14
相关论文
共 59 条
[1]   Resilient Nodeless d-Wave Superconductivity in Monolayer FeSe [J].
Agterberg, D. F. ;
Shishidou, T. ;
O'Halloran, J. ;
Brydon, P. M. R. ;
Weinert, M. .
PHYSICAL REVIEW LETTERS, 2017, 119 (26)
[2]   Superconducting properties of the s±-wave state: Fe-based superconductors [J].
Bang, Yunkyu ;
Stewart, G. R. .
JOURNAL OF PHYSICS-CONDENSED MATTER, 2017, 29 (12)
[3]   A shadow gap in the over-doped (Ba1-XKX)Fe2As2 compound [J].
Bang, Yunkyu .
NEW JOURNAL OF PHYSICS, 2014, 16
[4]   Odd-frequency superconducting pairing in multiband superconductors [J].
Black-Schaffer, Annica M. ;
Balatsky, Alexander V. .
PHYSICAL REVIEW B, 2013, 88 (10)
[5]  
Bogolyubov N.N., 1959, NEW METHOD THEORY SU
[6]   Superconductivity in Fe-chalcogenides [J].
Chang, C. C. ;
Chen, T. K. ;
Lee, W. C. ;
Lin, P. H. ;
Wang, M. J. ;
Wen, Y. C. ;
Wu, P. M. ;
Wu, M. K. .
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, 2015, 514 :423-434
[7]   Superconductivity in the presence of spin-orbit interactions stabilized by Hund coupling [J].
Cheung, Alfred K. C. ;
Agterberg, D. F. .
PHYSICAL REVIEW B, 2019, 99 (02)
[8]  
Chubukov A, 2015, SPRINGER SER MATER S, V211, P255, DOI 10.1007/978-3-319-11254-1_8
[9]   Displacement and annihilation of Dirac gap nodes in d-wave iron-based superconductors [J].
Chubukov, Andrey V. ;
Vafek, Oskar ;
Fernandes, Rafael M. .
PHYSICAL REVIEW B, 2016, 94 (17)
[10]   Magnetism, Superconductivity, and Spontaneous Orbital Order in Iron-Based Superconductors: Which Comes First and Why? [J].
Chubukov, Andrey V. ;
Khodas, M. ;
Fernandes, Rafael M. .
PHYSICAL REVIEW X, 2016, 6 (04)