Direct observation of competition between superconductivity and charge density wave order in YBa2Cu3Oy

Understand

Superconductivity often emerges in the proximity of, or in competition with, symmetry breaking ground states such as antiferromagnetism or charge density waves (CDW)1-5.

• A number of materials in the cuprate family, which includes the high-transition-temperature (high-Tc) superconductors, show spin and charge density wave order5-7.
• Thus a fundamental question is to what extent these ordered states exist for compositions close to optimal for superconductivity.
• Here we use high-energy x-ray diffraction to show that a CDW develops at zero field in the normal state of superconducting YBa2Cu3O6.67 (Tc = 67 K).