Slow Quantum Oscillations without Fine-Grained Fermi Surface Reconstruction in Cuprate Superconductors

The Fourier transform of the observed magnetic quantum oscillations (MQOs) in YBa2Cu3O6+delta high-temperature superconductors has a prominent low-frequency peak with two smaller neighboring peaks. The separation and positions of these three peaks are almost independent of doping. This pattern has been explained previously by rather special, exquisitely detailed, Fermi-surface reconstruction. We propose that these MQOs have a different origin, and their frequencies are related to the bilayer and inter-bilayer electron hopping rather than directly to the areas of tiny Fermi-surface pockets. Such so-called "slow oscillations" explain more naturally many features of the observed oscillations and allow us to estimate the inter-layer transfer integrals and in-plane Fermi momentum.