Electronic band structure and momentum dependence of the superconducting gap in (Ca, Na)Fe2As2 from angle-resolved photoemission spectroscopy

D. V. Evtushinsky; V. B. Zabolotnyy; L. Harnagea; A. N. Yaresko; S. Thirupathaiah; A. A. Kordyuk; J. Maletz; S. Aswartham; S. Wurmehl; E. Rienks; R. Follath; B. Büchner; S. V. Borisenko

doi:10.1103/physrevb.87.094501

arXiv · 1211.4593

Electronic band structure and momentum dependence of the superconducting gap in (Ca, Na)Fe2As2 from angle-resolved photoemission spectroscopy

D. V. Evtushinsky·V. B. Zabolotnyy·L. Harnagea·A. N. Yaresko·S. Thirupathaiah·A. A. Kordyuk·J. Maletz·S. Aswartham·S. Wurmehl·E. Rienks·R. Follath·B. Büchner·S. V. Borisenko

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Abstract

Electronic structure of newly synthesized single crystals of calcium iron arsenide doped with sodium with Tc ranging from 33 to 14 K has been determined by angle-resolved photoemission spectroscopy (ARPES). The measured band dispersion is in general agreement with theoretical calculations, nonetheless implies absence of Fermi surface nesting at antiferromagnetic vector. A clearly developing below Tc strongly band-dependant superconducting gap has been revealed for samples with various doping levels. BCS ratio for optimal doping, $2Δ/k_{\rm B}T_{\rm c}=5.5$, is substantially smaller than the numbers reported for related compounds, implying a non-trivial relation between electronic dispersion and superconducting gap in iron arsenides.

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D. V. Evtushinsky, V. B. Zabolotnyy, L. Harnagea, A. N. Yaresko, S. Thirupathaiah, A. A. Kordyuk, J. Maletz, S. Aswartham, S. Wurmehl, E. Rienks, R. Follath, B. Büchner, S. V. Borisenko. 2012-11-19. Electronic band structure and momentum dependence of the superconducting gap in (Ca, Na)Fe2As2 from angle-resolved photoemission spectroscopy. https://doi.org/10.1103/physrevb.87.094501

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