Lifshitz critical point in the cuprate superconductorYBa2Cu3Oyfrom high-field Hall effect measurements

Abstract

The Hall coefficient RH of the cuprate superconductor YBa2Cu3Oy was measured in magnetic fields up to 60 T for a hole concentration p from 0.078 to 0.152, in the underdoped regime. In fields large enough to suppress superconductivity, RH(T ) is seen to go from positive at high temperature to negative at low temperature, for p > 0.08. This change of sign is attributed to the emergence of an electron pocket in the Fermi surface at low temperature. At p < 0.08, the normal-state RH(T ) remains positive at all temperatures, increasing monotonically as T → 0. We attribute the change of behaviour across p = 0.08 to a Lifshitz transition, namely a change in Fermi-surface topology occurring at a critical concentration pL = 0.08, where the electron pocket vanishes. The loss of the high-mobility electron pocket across pL coincides with a ten-fold drop in the conductivity at low temperature, revealed in measurements of the electrical resistivity ρ 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 ρ, showing that without its electron pocket the Fermi surface must have strong two-fold in-plane anisotropy. These findings are consistent with a Fermi-surface reconstruction caused by a unidirectional spin-density wave or stripe order. PACS numbers:arXiv:1009.2078v2 [cond-mat.supr-con]

Emergence of charge order from the vortex state of a high-temperature superconductor

“…These correlations are again a manifestation of the competition between superconductivity and charge order and they are consistent with charge order being strongest near p ¼ 0.115-0.12 (ref. 22), which is within the superconducting dome. This last observation is, however, puzzling.…”

Quantum oscillations in the high- T c cuprates

“…The top axis shows the corresponding oxygen concentration. In green is the temperature corresponding to the resistive upturn (from [4,81]), the red line denotes the superconducting transition temperature [82] (arbitrary units). Inset: plot of the nodal Fermi velocity as a function of hole doping in Bi2201 (cyan from [83], purple from [84]) showing a collapse in v F at low dopings subsequently found in ARPES studies.…”

Ong construction for the reconstructed Fermi surface of underdoped cuprates

“…5 of Ref. [22]. This implies that a large magnetic field is not necessary to induce the sign reversal in R H (T ) and in turn, that the HS model is not generally applicable to the UD Y-based cuprates.…”