The charge-density-wave signature on the superfluid density of cuprate superconductors

Abstract

The superfluid density or superconducting (SC) carrier concentration n sc of cuprates has been the subject of intense investigations but there is not any single theory capable to explain all the available data. Here we show that the behavior of n sc in under and overdoped cuprates are a consequence of an SC interaction based on charge fluctuations in the incommensurate charge-density-waves (CDW) domains. We have shown that this interaction scales with the CDW amplitude or the pseudogap (PG) energy, yielding local SC amplitudes and Josephson currents. The average Josephson energy is proportional to the phase stiffness or superfluid density ρ sc ∝ n sc. We find that n sc(p) increases almost linearly with doping p in the underdoped region and in the charge abundant overdoped only a few fractions of the holes condense leading to two kinds of carriers, a recently confirmed feature. The calculations and the ρ sc data uncover how the PG–CDW–SC intertwined orders operate to yield cuprates properties.