Mottness induced superfluid phase fluctuation with increased density

Abstract

Recent observations of diminishing superfluid phase stiffness in overdoped cuprate hightemperature superconductors challenges the conventional picture of superconductivity. Here, through analytic estimation and verified via variational Monte Carlo calculation of an emergent Bose liquid, we point out that Mottness of the underlying doped holes dictates a strong phase fluctuation of the superfluid at moderate carrier density. This effect turns the expected doping-increased phase stiffness into a dome shape, in good agreement with the recent observation. Specifically, the effective mass divergence due to "jamming" of the low-energy bosons reproduces the observed nonlinear relation between phase stiffness and transition temperature. Our results suggest a new paradigm, in which the high-temperature superconductivity in the cuprates is dominated by physics of Bose-Einstein condensation, as opposed to pairing-strength limited Cooper pairing.

Probing a Bose Metal via Electrons: Inescapable non-Fermi liquid scattering and pseudogap physics

“…For those interested in the cuprates, our successful reproduction of NFL scattering, PG formation, and many related symptoms found in the cuprates leads one to wonder whether the pseudogap regime of the cuprate phase diagram below T * is actually contained within the finite temperature phase of a Bose metal below a higher temperature T BM . In fact, the Bose metal mean field used here directly results from the phase frustrated regime [1,64] of the emergent Bose liquid theory [65,66] of the cuprates. Assuming this is true, then it is no wonder that the observations from single particle fermion probes such as ARPES and STM are so difficult to explain.…”