2015/04/07 by E. M. Forgan, Forgan, E. M., E. Blackburn +28
Chemistry · Engineering · Physics and Astronomy · #FOS: Physical sciences #Inorganic Fluorides and Related Compounds #Physics of Superconductivity and Magnetism #Superconducting Materials and Applications #Superconductivity (cond-mat.supr-con) #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.1504.01585
openalex publication_date 2015/04/07 · arxiv created 2015/09/28 · arxiv updated 2015/09/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
All underdoped high-temperature cuprate superconductors appear to exhibit charge density wave (CDW) order, but both the underlying symmetry breaking and the origin of the CDW remain unclear. We use X-ray diffraction to determine the microscopic structure of the CDW in an archetypical cuprate YBa2Cu3O6.54 at its superconducting transition temperature Tc ~ 60 K. We find that the CDWs present in this material break the mirror symmetry of the CuO2 bilayers. The ionic displacements in a CDW have two components: one perpendicular to the CuO2 planes, and another parallel to these planes, which is out of phase with the first. The largest displacements are those of the planar oxygen atoms and are perpendicular to the CuO2 planes. Our results allow many electronic properties of the underdoped cuprates to be understood. For instance, the CDW will lead to local variations in the doping (or electronic structure) giving an explicit explanation of the appearance of density-wave states with broken symmetry in scanning tunnelling microscopy (STM) and soft X-ray measurements.