Interaction-Driven Ferrimagnetic Stripes in the Extended Hubbard Model

TL;DR

This study reveals that short-range interactions in the extended Hubbard model can induce ferrimagnetic stripe order intertwined with charge density waves, significantly altering the magnetic ground state.

Contribution

It demonstrates that including nearest-neighbor repulsion $V$ in the Hubbard model can stabilize ferrimagnetic stripe phases, a novel magnetic order not seen with only on-site interactions.

Findings

Ferrimagnetic stripes emerge above a critical $V/U$ ratio.

The order persists with next-nearest-neighbor hopping $t'$.

Short-range interactions can stabilize new magnetic textures.

Abstract

Long-range interactions can qualitatively reorganize correlated-electron ground states. In the square-lattice Hubbard model, on-site repulsion produces antiferromagnetic spin and charge stripes upon doping. We show that including a nearest-neighbor repulsion $V$ can dramatically alter this behavior. Using auxiliary-field quantum Monte Carlo and density matrix renormalization group methods, we find that, above a critical ratio $V/U$ ($\sim 0.25$), the system develops a modulated ferrimagnetic order intertwined with checkerboard charge-density-wave. Inside the ferrimagnetic domains, spin density alternates between positive (or negative) and nearly zero values. When the total spin is fixed to zero, positive and negative domains alternate in space; when spins are unconstrained, a ferrimagnetic state emerges with finite magnetization. Including a next-nearest-neighbor hopping $t'$ changes the modulation wavelength but leaves the order robust. Our results demonstrate that even short-range nonlocal interactions can stabilize qualitatively new magnetic textures, with implications for cuprate materials and programmable quantum simulators.