Enhancement of d-wave Pairing in Strongly Correlated Altermagnet

TL;DR

This study shows that in an altermagnetic state, increasing anisotropy enhances d-wave pairing correlations, suggesting a new route to unconventional superconductivity without doping.

Contribution

It introduces a model where spin-dependent hopping in altermagnetism boosts d-wave pairing, revealing a doping-free pathway to superconductivity.

Findings

Anisotropy suppresses antiferromagnetic order.

Enhanced d-wave pairing correlations observed.

Potential for doping-free unconventional superconductivity.

Abstract

Altermagnetism, featuring momentum-dependent spin splitting without net magnetization, has attracted a growing interest for spintronics. We study a Fermi Hubbard model with altermagnetic order arising from the spin-anisotropic hopping near half-filling using constrained-path quantum Monte Carlo. Spin-dependent hopping breaks SU(2) symmetry and disrupts Fermi surface nesting, giving rise to an altermagnetic state with momentum-space spin splitting but no net magnetization. We find that increasing anisotropy suppresses long-range antiferromagnetic order and significantly enhances effective $d$-wave pairing correlations. Our results demonstrate a doping-free route to unconventional superconductivity mediated by short-range spin fluctuations in an altermagnetic background.