The Three-Dimensional Electronic Structure of LiFeAs: Strong-coupling Superconductivity and Topology in the Iron Pnictides

Abstract

Amongst the iron-based superconductors, LiFeAs is unrivalled in the simplicity of its crystal structure and phase diagram. However, our understanding of this canonical compound suffers from conflict between mutually incompatible descriptions of the material's electronic structure, as derived from contradictory interpretations of the photoemission record. Here, we explore the challenge of interpretation in such experiments. By combining comprehensive photon energy- and polarization- dependent angle-resolved photoemission spectroscopy (ARPES) measurements with numerical simulations, we establish the providence of several contradictions in the present understanding of this and related materials. We identify a confluence of surface-related issues which have precluded unambiguous identification of both the number and dimensionality of the Fermi surface sheets. Ultimately, we arrive at a scenario which supports indications of topologically non-trivial states, while also being incompatible with superconductivity as a spin-fluctuation driven Fermi surface instability.

8 pages, 4 figures

References in corpus (12)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• LiFeAs: An Intrinsic FeAs-based Superconductor with Tc = 18K
• A precise method for visualizing dispersive features in image plots
• Anisotropic Energy Gaps of Iron-based Superconductivity from Intra-band Quasiparticle Interference in LiFeAs
• Formation of Hubbard-like bands as a fingerprint of strong electron-electron interactions in FeSe
• Scanning tunneling spectroscopy of superconducting LiFeAs single crystals: Evidence for two nodeless energy gaps and coupling to a bosonic mode
• Observation of strong electron pairing on bands without Fermi surfaces in LiFe1-xCoxAs
• Hund interaction, spin-orbit coupling and the mechanism of superconductivity in strongly hole-doped iron pnictides
• Multiorbital effects on the transport and the superconducting fluctuations in LiFeAs
• Crystalline symmetry protected helical Majorana modes in the iron pnictides
• Incommensurate antiferromagnetic fluctuations in single-crystalline LiFeAs studied by inelastic neutron scattering

Cited by in corpus (4)

• Competing Vortex Topologies in Iron-based Superconductors
• Advancing time- and angle-resolved photoemission spectroscopy: The role of ultrafast laser development
• Looking Beyond the Surface with Angle-Resolved Photoemission Spectroscopy
• Quasiparticle interference in LiFeAs: Signature of inelastic tunneling through spin fluctuations