Superfluid Density in High-$T_c$ Superconductors: Enabled by Holes or Suppressed by Electrons?

TL;DR

This paper proposes that the superfluid density in high-$T_c$ superconductors is primarily influenced by electron competition with antiferromagnetism, challenging the view that it results from hole pairing in the Mott insulator state.

Contribution

It introduces a new perspective linking superfluid density dependence on doping to antiferromagnetic competition rather than hole pairing.

Findings

Correlation energy increases with finite pairing wavevector under strong antiferromagnetic fluctuations.

Doping dependence of phase stiffness is attributed to electron-antiferromagnetism competition.

Challenges the conventional hole-pairing interpretation of superfluid density behavior.

Abstract

The critical temperature of an underdoped cuprate superconductor is limited by its phase stiffness $\rho$. In this Letter we argue that the dependence of $\rho$ on doping $x$ should be understood as a consequence of deleterious competition with antiferromagnetism at large electron densities, rather than as evidence for pairing of holes in the $x =0$ Mott insulator state. Our proposal is based on the observation that the correlation energy of a d-wave superconductor increases in magnitude at finite pairing wavevector when antiferromagnetic fluctuations are strong.