Superfluid Suppression in d-Wave Superconductors due to Disordered Magnetism

TL;DR

This paper models how disordered magnetic correlations, specifically spin density waves, suppress superfluid density in d-wave superconductors, aligning with experimental observations in underdoped YBCO.

Contribution

It introduces a self-consistent calculation of superfluid density considering incommensurate SDW coexistence with superconductivity, explaining experimental suppression in underdoped cuprates.

Findings

Disordered SDW lead to density of states similar to dirty d-wave superconductors.

Superfluid density collapse at x≈0.35 in YBCO can be explained by SDW coexistence.

Inhomogeneous doping results in superfluid behavior consistent with experimental data.

Abstract

The influence of static magnetic correlations on the temperature-dependent superfluid density \rho_s(T) is calculated for d-wave superconductors. In self-consistent calculations, itinerant holes form incommensurate spin density waves (SDW) which coexist with superconductivity. In the clean limit, the density of states is gapped, and \rho_s(T << T_c) is exponentially activated. In inhomogeneously-doped cases, the SDW are disordered and both the density of states and \rho_s(T) obtain forms indistinguishable from those in dirty but pure d-wave superconductors, in accordance with experiments. We conclude that the observed collapse of \rho_s at x\approx 0.35 in underdoped YBCO may plausibly be attributed to the coexistence of SDW and superconductivity.