Isotropic multi-gap superconductivity in BaFe1.9Pt0.1As2 from thermal transport and spectroscopic measurements

Abstract

Thermal conductivity, point contact spectroscopy, angle-resolved photoemission and Raman spectroscopy measurements were performed on BaFe1.9Pt0.1As2 single crystals obtained from the same synthesis batch in order to investigate the superconducting energy gap structure using multiple techniques. Low temperature thermal conductivity was measured in the superconducting state as a function of temperature and magnetic field, revealing an absence of quasiparticle excitations in the T=0 limit up to 15 T applied magnetic fields. Point-contact Andreev reflection spectroscopy measurements were performed as a function of temperature using the needle-anvil technique, yielding features in the conductance spectra at both 2.5 meV and 7.0 meV scales consistent with a multi-gap scenario. Angle-resolved photoemission spectroscopy probed the electronic band structure above and below the superconducting transition temperature of T_c=23 K, revealing an isotropic gap of magnitude ~3 meV on both electron and hole pockets. Finally, Raman spectroscopy was used to probe quasiparticle excitations in multiple channels, showing a threshold energy scale of 3 meV below T_c. Overall, we find strong evidence for an isotropic gap structure with no nodes or deep minima in this system, with a 3 meV magnitude gap consistently observed and a second, larger gap suggested by point contact spectroscopy measurements. We discuss the implications that the combination of these results reveal about the superconducting order parameter in the BaFe1-xPtxAs2 system and how this relates to similar substituted iron pnictides.

arXiv comment12 pages, 9 figures; invited submission for SUST focus issue on Multicomponent Superconductivity

References in corpus (43)

• The Puzzle of High Temperature Superconductivity in Layered Iron Pnictides and Chalcogenides
• Superconductivity in Iron Compounds
• High-temperature superconductivity in iron-based materials
• Gap symmetry and structure of Fe-based superconductors
• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Strong surface scattering in ultrahigh mobility Bi2Se3 topological insulator crystals
• Fermi surface nesting induced strong pairing in iron-based superconductors
• Superconductivity without magnetism in LiFeAs
• Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity
• Scanning Tunneling Spectroscopy and Vortex Imaging in the Iron-Pnictide Superconductor BaFe${}_{1.8}$Co${}_{0.2}$As${}_2$
• Heat Conduction in the Vortex State of NbSe_2: Evidence for Multi-Band Superconductivity
• Heat Transport in a Strongly Overdoped Cuprate: Fermi Liquid and Pure d-wave BCS Superconductor
• Universal Heat Conduction in YBa_2Cu_3O_6.9
• The role of critical current on point contact Andreev Reflection spectrum between a normal metal and a superconductor
• Superconducting gap symmetry of Ba0.6K0.4Fe2As2 studied by angle-resolved photoemission spectroscopy
• Spectroscopic scanning tunneling microscopy insights into Fe-based superconductors
• Anisotropic Energy Gaps of Iron-based Superconductivity from Intra-band Quasiparticle Interference in LiFeAs
• Universal heat conduction in the iron-arsenide superconductor KFe2As2 : Evidence of a d-wave state
• Unconventional Anisotropic s-Wave Superconducting Gaps of LiFeAs Iron-Pnictide Superconductor
• Fe-based superconductors: an angle-resolved photoemission spectroscopy perspective
• Nodes in the gap structure of the iron-arsenide superconductor Ba(Fe_{1-x}Co_x)_2As_2 from c-axis heat transport measurements
• Superconducting and ferromagnetic phases induced by lattice distortions in SrFe2As2
• Directional point-contact Andreev-reflection spectroscopy of Fe-based superconductors: Fermi surface topology, gap symmetry, and electron-boson interaction
• Evidence for two-gap superconductivity in (Ba,K)Fe_2As_2 by directional point contact Andreev reflection spectroscopy
• Universality of superconducting gaps in overdoped Ba0.3K0.7Fe2As2 observed by angle-resolved photoemission spectroscopy
• Band and momentum dependent electron dynamics in superconducting $\mathrm{Ba}(\mathrm{F}{\mathrm{e}}_{1-\mathrm{x}}\mathrm{C}{\mathrm{o}}_{\mathrm{x}}{)}_2\mathrm{A}{\mathrm{s}}_2$ as seen via electronic Raman scattering
• Point contact Andreev reflection spectroscopy of superconducting energy gaps in 122-type family of iron pnictides
• From d-wave to s-wave pairing in the iron-pnictide superconductor (Ba,K)Fe2As2
• Pinpointing Gap Minima in Ba(Fe${}_{0.94}$Co${}_{0.06}{)}_2$As${}_2$ \textit{via} Band Structure Calculations and Electronic Raman Scattering
• Superconductivity at 23 K in Pt doped BaFe2As2 single crystals
• Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements
• Universal pair-breaking in transition metal-substituted iron-pnictide superconductors
• Superconductivity induced by doping Platinum in BaFe2As2
• Impact of the Spin Density Wave Order on the Superconducting Gap of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Point-contact spectroscopic studies on normal and superconducting AFe_2As_2-type iron-pnictide single crystals
• Superconducting energy gap distribution in c-axis oriented MgB${}_2$ thin film from point contact study
• Evidence of a universal and isotropic 2Δ/kBTC ratio in 122-type iron pnictide superconductors over a wide doping range
• Superconductivity and magnetism in platinum-substituted SrFe2As2 single crystals
• Probing the Order Parameter of Superconducting LiFeAs using Pb/LiFeAs and Au/LiFeAs Point-Contact Spectroscopy
• Screening of the Raman response in multiband superconductors -- application to iron-pnictides
• Spatial distributions in static heavy-light mesons: a comparison of quark models with lattice QCD
• Point Contact Spectroscopy of Fe Pnictides & Chalcogenides In The Normal State
• Reply to: ``Comment on `Polynomial-Time Simulation of Pairing Models on a Quantum Computer'''

Cited by in corpus (3)

• Emergent phenomena in multicomponent superconductivity: an introduction to the focus issue
• Influence of the Fermi surface geometry on a Josephson effect between an iron-pnictide and conventional superconductors
• Strong electron-boson coupling in the iron-based superconductor BaFe1.9Pt0.1As2 revealed by infrared spectroscopy