Abstract
The electrical resistivity of the underdoped cuprate superconductor YBaCuO was measured perpendicular to the CuO planes on ultrahigh quality single crystals in magnetic fields large enough to suppress superconductivity. The incoherent insulating-like behavior of at high temperature, characteristic of all underdoped cuprates, is found to cross over to a coherent regime of metallic behavior at low temperature. This crossover coincides with the emergence of the small electron pocket detected in the Fermi surface of YBaCuO via quantum oscillations, the Hall and Seebeck coefficients, and with the detection of a unidirectional modulation of the charge density as seen by high-field nuclear magnetic resonance measurements. The low coherence temperature is quantitatively consistent with the small hopping integral inferred from the splitting of the quantum oscillation frequencies. We conclude that the Fermi-surface reconstruction in YBaCuO at dopings from to at least , attributed to stripe order, produces a metallic state with three-dimensional coherence deep in the underdoped regime.
- Received 27 July 2011
DOI:https://doi.org/10.1103/PhysRevB.85.224524
©2012 American Physical Society