Accurate determination of the Fermi surface of tetragonal FeS via quantum oscillation measurements and quasiparticle self-consistent \textit{GW} calculations

TL;DR

This study combines quantum oscillation measurements and quasiparticle self-consistent GW calculations to accurately map the Fermi surface of tetragonal FeS, revealing detailed electronic structure insights relevant for superconductivity.

Contribution

The paper provides the first detailed experimental and theoretical determination of FeS's Fermi surface, achieving high accuracy with minimal band-energy adjustments and elucidating implications for superconducting gap structure.

Findings

All eight predicted Fermi surface cross sections observed experimentally.

Maximum deviation between calculations and measurements is less than 0.2% of the Brillouin zone area.

Carrier density is approximately 0.5 carriers per Fe atom.

Abstract

We perform de Haas-van Alphen measurements and quasiparticle self-consistent \textit{GW} (QS\textit{GW}) calculations on FeS. The calculated Fermi surface (FS) consists of two hole and two electron cylinders. We observe all the eight predicted FS cross sections experimentally. With momentum-independent band-energy adjustments of less than 0.1 eV, the maximum deviation between the calculated and observed cross sections is less than 0.2\% of the Brillouin zone area for $B \parallel c$. The carrier density is $\sim$0.5 carriers/Fe. The mass enhancements are nearly uniform across the FS cylinders and moderate, $\sim$2. The absence of a third hole cylinder with $d_{xy}$ character is favorable for the formation of a nodal superconducting gap.