The ubiquity of charge-density waves (CDW) in cuprate superconductors is now well established but key aspects of their microscopic structure are not clear yet.
In this work, we used nuclear magnetic resonance (NMR) to study the CDW induced by intense magnetic fields in the superconducting state of YBa2Cu3Oy. Being devoid of strong disorder effects, magnetic ordering and competition with superconductivity, this phase is likely to represent the paradigmatic form of CDW in the cuprates.
We show that this CDW is oxygen-centered, propagates along a single direction and has a local commensurate period of three unit cells, locked to the lattice, despite its incommensurate global periodicity measured in X-ray scattering and possibly dictated by the Fermi surface.
Publication - Locally commensurate charge-density wave with three-unit-cell periodicity in YBCO
Vinograd, I. et al. Nat Commun 12, 3274 (2021).
Figure - representative 17O NMR line shape in YBa2Cu3O6.56 at T = 2 K and B » 28 T. The 2:1 relative area of the two peaks is evidence that the local CDW period is three unit-cell long.