Three-dimensional electronic structure of LiFeAs

Among the iron-based superconductors, LiFeAs is unrivaled 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 the dimensionality of the Fermi-surface sheets. Ultimately, we arrive at a scenario which supports indications of topologically nontrivial states while also being incompatible with superconductivity as a spin-fluctuation-driven Fermi-surface instability.