Magnetic penetration depth in the presence of a spin-density wave in multiband superconductors at zero temperature

TL;DR

This paper provides a theoretical analysis of how the London penetration depth behaves in multiband superconductors with coexisting superconducting and spin-density wave orders at zero temperature, highlighting the effects of doping and anisotropy.

Contribution

It introduces a model describing the penetration depth in multiband superconductors with competing orders, emphasizing the impact of spin-density waves on superfluid density and anisotropic properties.

Findings

Superfluid density follows the superconducting order parameter with doping.

Penetration depth saturates to BCS value in pure superconducting state.

Strong in-plane anisotropy induced by spin-density wave order.

Abstract

We present a theoretical description of the London penetration depth of a multi-band superconductor in the case when both superconducting and spin-density wave orders coexist. We focus on clean systems and zero temperature to emphasize the effect of the two competing orders. Our calculation shows that the supefluid density closely follows the evolution of the superconducting order parameter as doping is increased, saturating to a BCS value in the pure superconducting state. Furthermore, we predict a strong anisotropic in-pane penetration depth induced by the spin-density wave order.