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

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, $2\Delta /k_{\mathrm{B}}{T}_{\mathrm{c}}=5.5$, is substantially smaller than the numbers reported for related compounds, implying a non-trivial relation between electronic dispersion and superconducting gap in iron arsenides.

first ARPES on CNFA

References in corpus (11)

• High-temperature superconductivity in iron-based materials
• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Iron based superconductors: magnetism, superconductivity and electronic structure
• Momentum dependence of the superconducting gap in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• (pi,pi)-electronic order in iron arsenide superconductors
• Momentum-resolved superconducting gap in the bulk of Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ from combined ARPES and $\mu$SR measurements
• On the multi-orbital band structure and itinerant magnetism of iron-based superconductors
• Crossover from weak to strong pairing in unconventional superconductors
• Evidence for two-gap superconductivity in (Ba,K)Fe_2As_2 by directional point contact Andreev reflection spectroscopy
• Interplay between magnetic properties and Fermi surface nesting in iron pnictides
• Point-contact Andreev-reflection spectroscopy in ReFeAsO_{1-x}F_x (Re = La, Sm): Possible evidence for two nodeless gaps

Cited by in corpus (4)

• Pseudogap from ARPES experiment: three gaps in cuprates and topological superconductivity
• ARPES experiment in fermiology of quasi-2D metals (Review Article)
• ARPES measurements of the superconducting gap of Fe-based superconductors and their implications to the pairing mechanism
• Lower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap