Single reconstructed Fermi surface pocket in an underdoped single layer cuprate superconductor

TL;DR

This study uses high-resolution quantum oscillation measurements on HgBa2CuO4+d to reveal a single reconstructed Fermi surface pocket, supporting a biaxial charge-density-wave origin of the pseudogap in underdoped cuprates.

Contribution

It provides clear evidence of a single Fermi surface pocket in Hg1201, clarifying the nature of Fermi surface reconstruction in this simpler cuprate superconductor.

Findings

Only a single quantum oscillation frequency observed.

Fermi surface consists of a single quasi-two-dimensional pocket.

Charge-density-wave order causes Fermi surface reconstruction.

Abstract

The observation of a reconstructed Fermi surface via quantum oscillations in hole-doped cuprates opened a path towards identifying broken symmetry states in the pseudogap regime. However, such an identification has remained inconclusive due to the multi-frequency quantum oscillation spectra and complications accounting for bilayer effects in most studies. We overcome these impediments with high resolution measurements on the structurally simpler cuprate HgBa2CuO4+d (Hg1201), which features one CuO2 plane per unit cell. We find only a single oscillatory component with no signatures of magnetic breakdown tunneling to additional orbits. Therefore, the Fermi surface comprises a single quasi-two-dimensional pocket. Quantitative modeling of these results indicates that biaxial charge-density-wave within each CuO2 plane is responsible for the reconstruction, and rules out criss-crossed charge stripes between layers as a viable alternative in Hg1201. Lastly, we determine that the characteristic gap between reconstructed pockets is a significant fraction of the pseudogap energy.