Microscopic parameters from high-resolution specific heat measurements on superoptimally substituted BaFe2(As1-xPx)(2) single crystals
Number of Authors: 6
2016 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 93, no 1, 014509Article in journal (Refereed) Published
We investigate the electronic specific heat of superoptimally substituted BaFe2(As1-x P-x(x))(2) single crystals in the superconducting state using high-resolution nanocalorimetry. From the measurements, we extract the substitution dependence of the condensation energy, superconducting gap Delta, and related microscopic parameters. We find that the anomalous scaling of the specific heat jump Delta C proportional to T-c(3) , found in many iron-based superconductors, in this system originates from a T-c-dependent ratio Delta/k(B)T(c) in combination with a substitution-dependent density of states N(epsilon(F)). A clear enhancement is seen in the effective mass m* as the composition approaches the value that has been associated with a quantum critical point at optimum substitution. However, a simultaneous increase in the superconducting carrier concentration n(s) yields a penetration depth lambda that decreases with increasing T-c without sharp divergence at the quantum critical point. Uemura scaling indicates that T-c is governed by the Fermi temperature T-F for this multiband system.
Place, publisher, year, edition, pages
2016. Vol. 93, no 1, 014509
IdentifiersURN: urn:nbn:se:su:diva-126896DOI: 10.1103/PhysRevB.93.014509ISI: 000368481300009OAI: oai:DiVA.org:su-126896DiVA: diva2:903977