Scanning tunneling spectroscopy of SmFeAsO0.85: Possible evidence for d-wave order parameter symmetry

Abstract

We report a scanning tunneling spectroscopy investigation of polycrystalline SmFeAsO0.85 having a superconducting transition at 52 K. On large regions of the sample surface the tunneling spectra exhibited V-shaped gap structures with no coherence peaks, indicating degraded surface properties. In some regions, however, the coherence peaks were clearly observed, and the V-shaped gaps could be fit to the theory of tunneling into a d-wave superconductor, yielding gap values between 8 to 8.5 meV, corresponding to the ratio 2D/KTc ~ 3.55 - 3.8, which is slightly above the BCS weak-coupling prediction. In other regions the spectra exhibited zero-bias conductance peaks, consistent with a d-wave order parameter symmetry.

References in corpus (14)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Andreev - Saint James reflections: a probe of cuprate superconductors
• The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
• 19-F NMR Investigation of Iron-pnictide Superconductor LaFeAsO(0.89)F(0.11)
• Point-Contact Spectroscopy of Iron-Based Layered Superconductor LaO${}_{0.9}$F${}_{0.1-\delta }$FeAs
• Superconducting energy gap and c-axis plasma frequency of (Nd,Sm)O0.82F0.18FeAs superconductors from infrared ellipsometry
• Point contact Andreev reflection spectroscopy of NdFeAsO_0.85
• Correlation of tunneling spectra with surface nano-morphology and doping in thin YBa2Cu3O7-delta films
• Hole superconductivity in Arsenic-Iron compounds
• Scanning tunneling spectroscopy of a-axis YBa_2Cu_3O_7-δfilms:k-selectivity and the shape of the superconductor
• Penetration of Andreev bound states into the ferromagnet in a SrRuO${}_3$/(110)YBa${}_2$Cu${}_3$O${}_{7-\delta }$ bilayer: a scanning tunneling spectroscopy study
• Anomalous proximity effect in gold coated (110) $YB{a}_{2}C{u}_3{O}_{7-\delta }$ films: Penetration of the Andreev bound states

Cited by in corpus (31)

• High - Temperature Superconductivity in Iron Based Layered Compounds
• Three orbital model for the iron-based superconductors
• Spectroscopic scanning tunneling microscopy insights into Fe-based 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
• Properties of a two orbital model for oxypnictide superconductors: Magnetic order, B_2g spin-singlet pairing channel, and its nodal structure
• Crossover from weak to strong pairing in unconventional superconductors
• Observation of the Josephson effect in Pb/(Ba,K)Fe2As2 single crystal junctions
• Renormalization group flow, competing phases, and the structure of superconducting gap in multi-band models of Iron based superconductors
• Local density of states and superconducting gap in the iron chalcogenide superconductor Fe${}_{1+\delta }$Se${}_{1-x}$Te${}_x$ observed by scanning tunneling spectroscopy
• Neutron and ARPES Constraints on the Couplings of the Multiorbital Hubbard Model for the Pnictides
• Andreev spectra and subgap bound states in multiband superconductors
• Nodal Superconductivity with Multiple Gaps in SmFeAsO${}_{0.9}$F${}_{0.1}$
• Nonmagnetic Impurity Resonances as a Signature of Sign-Reversal Pairing in the FeAs-based Superconductors
• Global Phase Diagram for Magnetism and Lattice Distortion of Fe-pnictide Materials
• Coexistence of two order parameters and a pseudogaplike feature in the iron-based superconductor LaFeAsO_(1-x)F_x
• Point-contact Andreev-reflection spectroscopy in ReFeAsO_{1-x}F_x (Re = La, Sm): Possible evidence for two nodeless gaps
• Experimental observables near a nematic quantum critical point in the pnictide and cuprate superconductors
• Surface-driven electronic structure in LaFeAsO studied by angle resolved photoemission spectroscopy
• Andreev spectroscopy of iron-based superconductors: temperature dependence of the order parameters and scaling of the ${\Delta }_{L,S}$ with $T_C$
• Surface density of states of s+-wave Cooper pairs in a two-band model
• Investigation of Superconducting Gap Structure in TbFeAsO${}_{0.9}$F${}_{0.1}$ using Point Contact Andreev Reflection
• Evolution of Superconducting Gaps in Th-Substituted Sm${}_{1-x}$Th${}_x$OFeAs Studied by Multiple Andreev Reflection Spectroscopy
• Observation of Multi-Gap Superconductivity in GdO(F)FeAs by Andreev Spectroscopy
• Determination of Superconducting Gap of SmFeAsFxO1-x Superconductors by Andreev Reflection Spectroscopy
• Disorder effects in pnictides : a tunneling spectroscopy study
• Theory of tunnelling into a multi-band superconductor: decoherence and interference
• A Unified Description of Cuprate and Iron Arsenide Superconductors
• Electronic Behavior of Superconducting SmFeAsO0.75
• Interrogating the superconductor Ca10(Pt4As8)(Fe2-xPtxAs2)5 Layer-by-layer
• Constraints Imposed by Symmetry on Pairing Operators for the Pnictides
• Minimal model of point contact Andreev reflection spectroscopy of multiband superconductors