Evolution of magnetic correlation in doped Hubbard model with altermagnetic spin splitting

TL;DR

This paper investigates how altermagnetic spin splitting influences magnetic correlations in the doped Hubbard model, revealing a transition from antiferromagnetic to spiral order and potential applications in spintronics.

Contribution

It introduces the effects of spin-dependent next-nearest-neighbor hopping on magnetic order in the Hubbard model, a novel exploration of altermagnetic phenomena.

Findings

Transition from antiferromagnetic to spiral magnetic order with increased spin anisotropy or doping

Identification of coexistence of stripe and spiral correlations in certain regimes

Potential for realizing non-collinear spin textures in altermagnetic systems

Abstract

The evolution of magnetic correlation in strongly correlated electron systems with altermagentic spin splitting remains largely unexplored. Here we investigate how spin splitting generated by spin-dependent next-nearest-neighbor hopping t' reshapes the Fermi surface nesting and van Hove singularities in the two-dimensional square-lattice Hubbard model, leading evolution of magnetic instabilities. Using the constrained-path quantum Monte Carlo method, we find the dominant magnetic correlation as functions of the filling and t'/t by computing the momentum-resolved spin structure factor. The analysis reveals a transition from antiferromagnetic ({\pi},{\pi}) order in the isotropic, half-filled system to non-collinear spiral ({\pi},q) order upon increasing the spin-dependent anisotropy or doping away from half-filling, ultimately entering a short-range correlation regime where stripe and spiral correlation coexist. These findings highlight a possible route to realizing spiral correlation in altermagnetic systems, potentially providing a platform for spintronic devices that exploit non-collinear spin textures.