Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor

Abstract

Under the Dome The superconducting transition temperature T c of copper oxides has a dome-shaped dependence on chemical doping. Whether there is a quantum critical point (QCP) beneath the dome, and whether it is related to the enigmatic pseudogap, has been heavily debated. Two papers address this question in two different families of Bi-based cuprates. In (Bi,Pb) 2 (Sr,La) 2 CuO 6+δ , He et al. (p. 608 ) found that the Fermi surface (FS) undergoes a topological change as doping is increased, which points to the existence of a QCP at a doping close to the maximum in T c , seemingly uncorrelated with the pseudogap. Fujita et al. (p. 612 ) studied a range of dopings in Bi 2 Sr 2 CaCu 2 O 8+δ to find an FS reconstruction simultaneous with the disappearance of both rotational and translational symmetry breaking, the latter of which has been associated with the pseudogap. These findings point to a concealed QCP.