Magnetic breakdown and quantum oscillations in electron-doped high temperature superconductor $\mathrm{Nd_{2-x}Ce_{x}CuO_{4}}$

TL;DR

This paper investigates quantum oscillations in the electron-doped superconductor Nd2-xCexCuO4 by modeling Fermi surface reconstruction and magnetic breakdown without quasiclassical approximations, explaining experimental observations.

Contribution

It introduces an exact transfer matrix approach to study high-field quantum oscillations in reconstructed Fermi surfaces, avoiding quasiclassical approximations and broadening assumptions.

Findings

Reveals coexistence of slow and fast quantum oscillations due to Fermi surface reconstruction.

Shows magnetic breakdown across small gaps explains observed oscillation patterns.

Demonstrates the method's applicability to models like d-density wave and spin density wave.

Abstract

Recent more precise experiments have revealed both a slow and a fast quantum oscillation in the c-axis resistivity of nearly optimal to overdoped electron-doped high temperature superconductor $\mathrm{Nd_{2-x}Ce_{x}CuO_{4}}$. Here we study this problem from the perspective of Fermi surface reconstruction using an exact transfer matrix method and the Pichard-Landauer formula. In this method, neither quasiclassical approximations for magnetic breakdown, nor {\em ad ho}c broadening of Landau levels, are necessary to study the high field quantum oscillations. The underlying Hamiltonian is a mean field Hamiltonian that incorporates a two-fold commensurate Fermi surface reconsruction. While the specific mean field considered is the $d$-density wave, similar results can also be obtained by a model of a spin density wave, as was explicitly demonstrated earlier. The results are consistent with an interplay of magnetic breakdown across small gaps in the reconstructed Fermi surface and Shubnikov-de Haas oscillations.