Direct observation of competition between superconductivity and charge density wave order in YBa2Cu3O6.67
Abstract
Superconductivity often emerges in the proximity of, or in competition with, symmetry-breaking ground states such as antiferromagnetism or charge density waves (CDW). A number of materials in the cuprate family, which includes the high transition-temperature (high-Tc) superconductors, show spin and charge density wave order. Thus a fundamental question is to what extent do 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=67K). This sample has a hole doping of 0.12 per copper and a well-ordered oxygen chain superstructure. Below Tc, the application of a magnetic field suppresses superconductivity and enhances the CDW. Hence, the CDW and superconductivity in this typical high-Tc material are competing orders with similar energy scales, and the high-Tc superconductivity forms from a pre-existing CDW environment. Our results provide a mechanism for the formation of small Fermi surface pockets, which explain the negative Hall and Seebeck effects and the `Tc plateau' in this material when underdoped.
- Publication:
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Nature Physics
- Pub Date:
- December 2012
- DOI:
- 10.1038/nphys2456
- arXiv:
- arXiv:1206.4333
- Bibcode:
- 2012NatPh...8..871C
- Keywords:
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- Condensed Matter - Superconductivity;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- Supplementary Information is available on request