Doping and temperature dependence of superfluid weights for high Tc cuprates

TL;DR

This paper investigates how superfluid weight in high-Tc cuprates depends on doping and temperature using an improved slave-boson approach, revealing linear temperature dependence at low doping and a dome-shaped Tc variation.

Contribution

It introduces an improved slave-boson method to analyze doping and temperature effects on superfluid weight in high-Tc cuprates, aligning theoretical results with experimental observations.

Findings

Superfluid weight decreases linearly with temperature at low doping.

Superconducting transition temperature Tc exhibits a dome shape with doping.

Overdoped region shows weakening of spin-charge coupling, reducing Tc.

Abstract

Using the improved slave-boson approach of the t-J Hamiltonian [Phys. Rev. B 64, 052501 (2001)] that we developed recently, we report the hole doping and temperature dependence of the superfluid weight. It is shown that at low hole doping concentration x and at low temperatures T there exists a propensity of a linear decrease of the superfluid weight $n_s/m^*$ with temperature, and a tendency of doping independence in the slope of $\frac{n_s}{m^*}(x,T)$ vs. T in accordance of the relation $\frac{n_s}{m^*}(x,T) = \frac{n_s}{m^*}(x,0) - \alpha T$ with $\alpha$, a constant. It is also demonstrated that Tc increases with hole doping concentration x, reaches a saturation(maximum) at optimal doping and decreases with increasing $x$ and $n_s/m^*$ in the overdoped region. Such a reflex (decreasing) behavior of Tc is attributed to the weakening of coupling between the spin(spinon pair order) and charge(holon pair order) degrees of freedom in the overdoped region. All of these findings are in agreement with $\mu$SR measurements.