Abstract
The Hall coefficient of the cuprate superconductor was measured in magnetic fields up to 60 T for a hole concentration from 0.078 to 0.152 in the underdoped regime. In fields large enough to suppress superconductivity, is seen to go from positive at high temperature to negative at low temperature, for . This change of sign is attributed to the emergence of an electron pocket in the Fermi surface at low temperature. At , the normal-state remains positive at all temperatures, increasing monotonically as . We attribute the change of behavior across to a Lifshitz transition, namely a change in Fermi-surface topology occurring at a critical concentration , where the electron pocket vanishes. The loss of the high-mobility electron pocket across coincides with a tenfold drop in the conductivity at low temperature, revealed in measurements of the electrical resistivity at high fields, showing that the so-called metal-insulator crossover of cuprates is in fact driven by a Lifshitz transition. It also coincides with a jump in the in-plane anisotropy of , showing that without its electron pocket, the Fermi surface must have strong twofold in-plane anisotropy. These findings are consistent with a Fermi-surface reconstruction caused by a unidirectional spin-density wave or stripe order.
6 More- Received 13 September 2010
DOI:https://doi.org/10.1103/PhysRevB.83.054506
©2011 American Physical Society
Viewpoint
Picking the cuprates’ Fermi pockets
Published 14 February 2011
Transport and quantum oscillations measurements in the cuprate superconductor point to density-wave order as an explanation for the peculiar doping evolution of the Fermi surface.
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