Single-particle tunneling spectroscopy and superconducting gaps in the layered iron-based superconductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi mathvariant="normal">KCa</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">Fe</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">As</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">F</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math>
Wen Shan Duan, Kailun Chen, Wenshan Hong, Xiaoyu Chen, Huan Yang, Shiliang Li, Huiqian Luo, Hai‐Hu Wen
Abstract
KCa${}_{2}$Fe${}_{4}$As4F${}_{2}$ and its sister compounds provide a new platform to study superconducting mechanism of iron-based superconductors. Using scanning tunneling microscopy/spectroscopy, the authors observe here a full gap feature with a gap value close to 4.6 meV in tunneling spectra measured in KCa${}_{2}$Fe${}_{4}$As4F${}_{2}$. Quasiparticle interference patterns only show the intraband scattering of the holelike $\ensuremath{\alpha}$ pocket. The derived Fermi energy of this band is only about 24 meV, which indicates a deviation from the basic requirement of the weak-coupling BCS theory.
Topics & Concepts
QuasiparticleSuperconductivityQuantum tunnellingCondensed matter physicsSpectroscopyScanning tunneling microscopeScanning tunneling spectroscopyFermi levelPhysicsScatteringCoupling (piping)Materials scienceNuclear physicsQuantum mechanicsElectronMetallurgyIron-based superconductors researchPhysics of Superconductivity and Magnetism