Quantum oscillations of ortho-II YBa_2Cu_3O_6.5

TL;DR

This paper investigates how the Fermi surface topology in ortho-II YBa_2Cu_3O_6.5 is affected by different orders, revealing that electron pockets are unaffected while hole pockets are sensitive, and relates findings to experimental quantum oscillations.

Contribution

It provides a detailed analysis of Fermi surface changes under ddw and AF orders in ortho-II YBa_2Cu_3O_6.5, clarifying the origin of quantum oscillations.

Findings

Electron pocket remains unaffected by ortho-II potential.

Three distinct quantum oscillations are associated with Fermi pockets.

Results support the electron pocket origin of observed quantum oscillations.

Abstract

Motivated by quantum oscillations observed in highly ordered ortho-II YBa_2Cu_3O_6.5, we study the Fermi surface topology of d-density wave (ddw) or antiferromagnetic (AF) ordering in the presence of the ortho-II potential. We find that the electron pocket is unaffected by the presence of the ortho-II potential. This further strengthens the proposal that quantum oscillations observed in ortho-II-free YBa_2Cu_4O_8 arise from an electron pocket. On the other hand, the hole pocket topology is sensitive to the ortho-II potential. We show there exist generically three distinct quantum oscillations associated with one electron-like and two hole-like Fermi pockets. We compare our results to the quantum oscillations observed in experiments. We discuss possible ways to distinguish between ddw and antiferromagnetic orders in a potential single-layer ortho-II material.