Significant Enhancement of Upper Critical Fields by Doping and Strain in Iron-Based Superconductors

Authors

C. Tarantini, Florida State University
A. Gurevich, Old Dominion UniversityFollow
J. Jaroszynski, Florida State University
F. Balakirev, Los Alamos National Laboratory
E. Bellingeri, CNR-SPIN
I Pallecchi, CNR-SPIN
C. Ferdeghini, CNR-SPIN
B. Shen, Chinese Academy of Sciences
H. H. Wen, Chinese Academy of Sciences

Document Type

Article

Publication Date

2011

DOI

10.1103/PhysRevB.84.184522

Publication Title

Physical Review B

Volume

84

Issue

18

Pages

184522

Abstract

We report measurements of 85 Tesla of the upper critical fields H_c2(T) on Ba_1-xK_xAs₂Fe₂ single crystals and FeSe_1-xTe_x films tuned by doping and strain. We observed an H_c2 enhancement by more than 25 T at low temperatures for the optimally doped Ba_1-xK_xAs₂Fe₂ as compared to the previous measurements and extraordinarily high slopes of dH_c2/dT = 250-500 T/K near T_c in FeSe _1-xTe_x, indicating almost-complete suppression of orbital pair breaking. Theoretical analysis of H_c2(T) suggests an inhomogeneous Fulde-Ferrel-Larkin-Ovchinnikov state below 10K for H//ab in the optimally doped Ba_1-xK_xAs₂Fe₂ and below 3K for H//c and 9K for H//ab in FeSe_1-xTe_x. The analysis also shows that Hc2 in a multiband Fe-based superconductor can be significantly enhanced by doping and strain by shrinking and expanding different pockets of the Fermi surface, which can be more effective than the conventional way of increasing H_c2 by nonmagnetic impurities.

Rights

© 2011 American Physical Society. All rights reserved.

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Original Publication Citation

Tarantini, C., Gurevich, A., Jaroszynski, J., Balakirev, F., Bellingeri, E., Pallecchi, I., Ferdeghini, C., Shen, B., Wen, H. H., & Larbalestier, D. C. (2011). Significant enhancement of upper critical fields by doping and strain in iron-based superconductors. Physical Review B, 84(18), 184522. https://doi.org/10.1103/PhysRevB.84.184522

ORCID

0000-0003-0759-8941 (Gurevich)

Repository Citation

Tarantini, C.; Gurevich, A.; Jaroszynski, J.; Balakirev, F.; Bellingeri, E.; Pallecchi, I; Ferdeghini, C.; Shen, B.; and Wen, H. H., "Significant Enhancement of Upper Critical Fields by Doping and Strain in Iron-Based Superconductors" (2011). Physics Faculty Publications. 904.
https://digitalcommons.odu.edu/physics_fac_pubs/904