Fermi surface of superconducting LaFePO determined by quantum oscillations

TL;DR

This study uses quantum oscillations to map the Fermi surface of LaFePO, revealing a quasi-two-dimensional structure with electron and hole pockets, and an effective mass enhancement, indicating proximity to density wave instabilities.

Contribution

First detailed experimental determination of LaFePO's Fermi surface using quantum oscillations, confirming theoretical predictions and revealing mass enhancement and nesting features.

Findings

Fermi surface matches band-structure calculations broadly

Quasiparticle mass is enhanced by a factor of ~2

Fermi surface features nearly-nested electron and hole pockets

Abstract

We report extensive measurements of quantum oscillations in the normal state of the Fe-based superconductor LaFePO, (Tc ~ 6 K) using low temperature torque magnetometry and transport in high static magnetic fields (45 T). We find that the Fermi surface is in broad agreement with the band-structure calculations with the quasiparticle mass enhanced by a factor ~2. The quasi-two dimensional Fermi surface consist of nearly-nested electron and hole pockets, suggesting proximity to a spin/charge density wave instability.