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

Ryan P. Day; MengXing Na; Manuel Zingl; Berend Zwartsenberg; Matteo Michiardi; Giorgio Levy; Michael Schneider; Doug Wong; Pinder Dosanjh; Tor M. Pedersen; Sergey Gorovikov; Shun Chi; Ruixing Liang; Walter N. Hardy; Douglas A. Bonn; Sergey Zhdanovich; Ilya S. Elfimov; Andrea Damascelli

doi:10.1103/physrevb.105.155142

arXiv · 2109.13276

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

Ryan P. Day·MengXing Na·Manuel Zingl·Berend Zwartsenberg·Matteo Michiardi·Giorgio Levy·Michael Schneider·Doug Wong·Pinder Dosanjh·Tor M. Pedersen·Sergey Gorovikov·Shun Chi·Ruixing Liang·Walter N. Hardy·Douglas A. Bonn·Sergey Zhdanovich·Ilya S. Elfimov·Andrea Damascelli

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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.

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Ryan P. Day, MengXing Na, Manuel Zingl, Berend Zwartsenberg, Matteo Michiardi, Giorgio Levy, Michael Schneider, Doug Wong, Pinder Dosanjh, Tor M. Pedersen, Sergey Gorovikov, Shun Chi, Ruixing Liang, Walter N. Hardy, Douglas A. Bonn, Sergey Zhdanovich, Ilya S. Elfimov, Andrea Damascelli. 2021-09-27. The Three-Dimensional Electronic Structure of LiFeAs: Strong-coupling Superconductivity and Topology in the Iron Pnictides. https://doi.org/10.1103/physrevb.105.155142

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