# Nodeless d-wave superconducting pairing due to residual antiferromagnetism in underdoped Pr$_{2-x}$Ce$_x$CuO$_{4-\delta}$

## TL;DR

This study reveals that in underdoped Pr$_{2-x}$Ce$_x$CuO$_{4-eta}$, residual antiferromagnetism causes nodeless d-wave superconductivity, with a transition to nodal behavior as doping increases and the Fermi surface evolves.

## Contribution

It introduces a model showing how residual antiferromagnetism leads to nodeless d-wave pairing in underdoped electron-doped cuprates, aligning with experimental observations.

## Key findings

- Underdoped samples exhibit nodeless low-temperature penetration depth.
- Increasing doping causes a transition to nodal d-wave behavior.
- The model explains the doping-dependent evolution of the Fermi surface.

## Abstract

We have investigated the doping dependence of the penetration depth vs. temperature in electron doped Pr$_{2-x}$Ce$_x$CuO$_{4-\delta}$ using a model which assumes the uniform coexistence of (mean-field) antiferromagnetism and superconductivity. Despite the presence of a $d_{x^2-y^2}$ pairing gap in the underlying spectrum, we find nodeless behavior of the low-$T$ penetration depth in underdoped case, in accord with experimental results. As doping increases, a linear-in-$T$ behavior of the penetration depth, characteristic of d-wave pairing, emerges as the lower magnetic band crosses the Fermi level and creates a nodal Fermi surface pocket.