Eight-Unit-Cell Electronic Modulations in Cuprates Originating from Local Molecular Orbitals
Phys. Rev. Lett. 137, 156001 – Published 5 October, 2026
DOI: https://doi.org/10.1103/lvpn-gblk
Abstract
The pair density wave state with eight-unit-cell () periodicity has been widely regarded as the primary order in cuprates, yet its existence and origin remain subjects of intense debate. Using spectroscopic imaging scanning tunneling microscopy, we observe spatial modulations of the electronic states with approximately periodicity in both the superconducting and insulating regimes of hole-doped cuprate. We find that the spatial patterns are generated by the formation of molecular orbitals by doped holes, which organize into plaquettes as the basic unit. Our results identify the molecular-orbital plaquette as the fundamental electronic building block in cuprates, while the pair density wave represents a spatial subharmonic that emerges at sufficiently high doping.