Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor

Abstract

The unclear relationship between cuprate superconductivity and the pseudogap state remains an impediment to understanding the high transition temperature (T(c)) superconducting mechanism. Here, we used magnetic field-dependent scanning tunneling microscopy to provide phase-sensitive proof that d-wave superconductivity coexists with the pseudogap on the antinodal Fermi surface of an overdoped cuprate. Furthermore, by tracking the hole-doping (p) dependence of the quasi-particle interference pattern within a single bismuth-based cuprate family, we observed a Fermi surface reconstruction slightly below optimal doping, indicating a zero-field quantum phase transition in notable proximity to the maximum superconducting T(c). Surprisingly, this major reorganization of the system's underlying electronic structure has no effect on the smoothly evolving pseudogap.

Electronic structure of the ingredient planes of the cuprate superconductorBi2Sr2CuO6+δ: A comparison study withBiLv1, Wang2, Ding3 et al. 2016Phys. Rev. B14160View full textAdd to dashboardCite

“…As a consequence, the doping efficiency by charge carriers in the BiO planes would be substantially lower than that in SrO. Given that the high-T c superconductivity develops with carrier doping of CuO 2 planes as seen in phase diagram 28,37 , our finding, the charge carriers are predominantly located around the BiO and SrO planes in Bi-2201 and Bi-2212, respectively, accounts excellently for why Bi-2212 has a higher T c, max than Bi-2201. Indeed, for pure Bi-2201, T c, max is generally lower than 20 K, whereas La-substituted Bi-2201 (Bi 2 Sr 2−x La x CuO 6+δ ) exhibits a higher T c, max > 30 K for x ∼ 0.4 24,40 .…”

“…A subsequent oxidation annealing can put the interstitial oxygen dopants back and recover the superconductivity of Bi-2201 studied [ Figs. 2(e-p)], judged by comparing the dI/dV spectra of BiO(I) plane with "standard" ones of the freshly cleaved superconducting Bi-2201 samples [25][26][27][28] . A closer inspection of these spectra under different annealing conditions has revealed three fundamental findings regarding cuprate superconductors, which we discuss in turn below.…”

Saturation of resistivity and Kohler's rule in Ni-dopedLa1.85Sr0.15CuO4cuprate

“…In the bismuth-based family, the expected linear relationship between n estimated from T C and from Luttinger count is obtained only assuming large surface from overdoped specimens down to p ∼ =0.145 inclusive [49]. In La 1.85 Sr 0.15 Cu 1−y Ni y O 4 , Ni doping effectively moves the system towards smaller p but the smooth evolution of all the fitted ρ(T ) parameters down to y=0 points toward small Fermi surface at p=0.15.…”

Interplay of chemical disorder and electronic inhomogeneity in unconventional superconductors

“…68 Recently, He et al used doping and magnetic field dependence of QPI to prove that d-wave Bogoliubov quasiparticles exist on the antinodal part of the Fermi surface, and to identify the competitive nature of superconductivity and the pseudogap. 69 Several possible defects have been suggested as the primary scattering sites responsible for this wealth of information from QPI in Bi-2212: interstitial O atoms, Sr or Cu site defects, and 2-3 nm sized ''patches'' of different spectral gaps. However, no consensus has been reached.…”