Fermi Surface Evolution in an Electron-Doped High-Tc Superconductor Revealed by Magnetic Quantum Oscillations

TL;DR

This study uses magnetic quantum oscillations to directly investigate how the Fermi surface in Nd$_{2-x}$Ce$_x$CuO$_4$ evolves with doping, revealing a significant topological change linked to symmetry breaking.

Contribution

It provides the first direct bulk measurement of Fermi surface changes across doping levels in an electron-doped high-Tc superconductor, highlighting the persistence of ordering beyond optimal doping.

Findings

Fermi surface topology changes sharply at a critical doping.

Translational symmetry breaking persists into the overdoped regime.

Survival of $(\pi/a,\pi/a)$ ordering at high doping levels.

Abstract

We report on the direct probing of the Fermi surface in the bulk of the electron-doped superconductor Nd$_{2-x}$Ce$_x$CuO$_4$ at different doping levels by means of magnetoresistance quantum oscillations. Our data reveal a sharp qualitative change in the Fermi surface topology, due to translational symmetry breaking in the electronic system which occurs at a critical doping level significantly exceeding the optimal doping. This result implies that the $(\pi/a,\pi/a)$ ordering, known to exist at low doping levels, survives up to the overdoped superconducting regime.