Collapse of the Normal-State Pseudogap at a Lifshitz Transition in theBi2Sr2CaCu2O

Abstract

We report a fine tuned doping study of strongly overdoped Bi_{2}Sr_{2}CaCu_{2}O_{8+δ} single crystals using electronic Raman scattering. Combined with theoretical calculations, we show that the doping, at which the normal-state pseudogap closes, coincides with a Lifshitz quantum phase transition where the active holelike Fermi surface becomes electronlike. This conclusion suggests that the microscopic cause of the pseudogap is sensitive to the Fermi surface topology. Furthermore, we find that the superconducting transition temperature is unaffected by this transition, demonstrating that their origins are different on the overdoped side.

Phase diagram of Bi2Sr2CaCu2O8+δ revisited

“…The T c , is also plotted. We first note that most of our data agree well with previous studies; gaps and transition temperatures from the present study follow the same trends with very little discrepancies 2,5,31–36 . The only adjustment needed for the perfect overlap with the previous studies was the shift in the doping level p A .…”

Three energy scales in the superconducting state of hole-doped cuprates detected by electronic Raman scattering

“…Preliminaries calculations advocate for this scenario but more deeper theoretical investigations are still required and will be developed in a near future. The Lifshitz transition in overdoped Bi-2212 has been first observed by ARPES in Bi-2212 [64] and recently detected by the analysis of the integrated Raman intensity as a function of doping level in Bi-2212 [65]. We found that p=0.22 is the starting point of the pseudogap as the doping decreases.…”

“…We suspect that at least the p=0.22 and 0.12 doping levels are directly connected to the doping evolution of the antinodal Bogoliubov quasiparticles spectral weight at low energy. p=0.22 corresponds to the doping level for which a Lifshitz transition occurs [64,65] and the antinodal quasiparticles spectral weight is strongly increased. On the other hand, p=0.12 corresponds to the doping level for which the charge ordering is well settled [71][72][73][74][75][76][77] and the antinodal quasiparticles spectral weight is strongly reduced.…”

Comprehensive phase diagram of two-dimensional space charge doped Bi2Sr2CaCu2O8+x

“…The downward deviation below T * in BSCCO-2212 is ascribed to the reduction of inelastic scattering rate of electrons in the pseudo-gap phase, when temperature is lowered 30 . This characteristic T * may however be different 2 from the temperature of crossover into the pseudo-gap phase T pg , commonly detected by photo-emission, Raman, or tunneling spectroscopy 17, 31, 32 . It is well established in cuprates that in the Fermi liquid phase the upward deviation of R s ( T ) below T m follows the power law , where the exponent m is expected to increase with doping from 1 to 1.5–2 depending on the material 3, 4, 33 .…”

“…This value is indicative of the change introduced by doping and not an absolute measure of the carrier density since the electronic structure at the Fermi surface and its evolution with doping and temperature is complex and cannot be approximated by a single parabolic band. The Fermi surface evolves from hole-like to electron-like with doping and the contributions of these surfaces to the Hall coefficient are temperature dependent 15–17 . To minimize errors related to this dependence, we consider R H values at the fixed, low temperature of 120 K 18, 19 for all doping values.…”