Evidence for multiple gaps in specific heat of LiFeAs crystals

Abstract

The zero-field specific heat of LiFeAs was measured on several single crystals selected from a bulk sample. A sharp Delta Cp/Tc anomaly of approximately 20 mJ/(mole x K^2) was observed. The value appears to be between those of SmFeAs(O0.9F0.1) and (Ba0.6K0.4)Fe2As2, but bears no clear correlation with their Sommerfeld coefficients. The electronic specific heat below Tc further reveals a two-gap structure with the narrower one only on the order of 0.7 meV. While the results are in rough agreement with the Hc1(T) previously reported on both LiFeAs and (Ba0.6K0.4)Fe2As2, they are different from the published specific-heat data of a (Ba0.6K0.4)Fe2As2 single crystal.

19 pages, 5 figures

References in corpus (17)

• LaFeAsO${}_{1-x}$F${}_x$: A low carrier density superconductor near itinerant magnetism
• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• LiFeAs: An Intrinsic FeAs-based Superconductor with Tc = 18K
• Competing Orders and Spin-Density-Wave Instability in La(O${}_{1-x}$F${}_x$)FeAs
• Very High Field Two-Band Superconductivity in LaFeAsO_0.89F_0.11
• The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
• Fully Gapped Superconducting State Based on a High Normal State Quasiparticle Density of States in Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ Single Crystals
• Low temperature specific heat of the hole-doped Ba_{0.6}K_{0.4}Fe_2As_2 single crystals and electron-doped SmFeAsO_{0.9}F_{0.1} samples
• Evidence for Two Gaps and Breakdown of the Uemura Plot in Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ Single Crystals
• Specific heat measurements of the gap structure of the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2
• Superconductivity: Exotic Commonalities in Phase and Mode
• Point-contact Andreev-reflection spectroscopy in ReFeAsO_{1-x}F_x (Re = La, Sm): Possible evidence for two nodeless gaps
• Thermal properties of SmFeAs(O1-xFx) as probe of the interplay between electrons and phonons
• Heat capacity measurements on FeAs-based compounds: a thermodynamic probe of electronic and magnetic states
• Lower Critical Field, Anisotropy, and Two-Gap Features of LiFeAs
• Coexistence of Supercondcutivity and Magnetism in LaFeAs(O0.94F0.06) Probed by Muon Spin Relaxation

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• Single crystal growth and superconducting properties of LiFeAs
• Anomalous proximity effects at the interface of s and s+- superconductors
• Investigation of LiFeAs by means of "Break-junction" Technique
• Multiband superconductivity and a deep gap minimum from the specific heat in KCa${}_2$(Fe${}_{1-x}$Ni${}_x$)${}_4$As${}_4$F${}_2$ ($x$ = 0, 0.05, 0.13)