Tuning Kinetic Magnetism of Strongly Correlated Electrons via Staggered Flux

TL;DR

This paper investigates how staggered magnetic flux can tune the kinetic magnetism in strongly correlated electron systems, revealing a quantum phase transition from ferromagnetic to antiferromagnetic states across various lattice geometries.

Contribution

It demonstrates a universal mechanism to control magnetic states via flux modulation in Hubbard models, highlighting a quantum critical point between distinct magnetic orders.

Findings

Ground state transitions from ferromagnetic to antiferromagnetic at critical flux

Kinetic origin of magnetic states confirmed by energy and correlation signals

Applicable to chains, ladders, and 2D lattices with various geometries

Abstract

We explore the kinetic magnetism of the infinite-$U$ repulsive Hubbard models at low hole densities on various lattices with nearest-neighbor hopping integrals modulated by a staggered magnetic flux $\pm\phi$. Tuning $\phi$ from 0 to $\pi$ makes the ground state (GS) change from a Nagaoka-type ferromagnetic state to a Haerter-Shastry-type antiferromagnetic state at a critical $\phi_c$, with both states being of kinetic origin. Intra-plaquette spin correlation, as well as the GS energy, signals such a quantum criticality. This tunable kinetic magnetism is generic, and appears in chains, ladders and two-dimensional lattices with squares or triangles as elementary constituents.