Spin-spiral instability of the Nagaoka ferromagnet in the crossover between square and triangular lattices
Abstract
We study the hard-core Fermi-Hubbard model in the crossover between square and triangular lattices near half-filling. As was recognized by Nagaoka in the 1960s, on the square lattice the presence of a single hole leads to ferromagnetic spin ordering. On the triangular lattice, geometric frustration instead leads to a spin-singlet ground state, which can be associated with a 120-degree spiral order. On lattices which interpolate between square and triangular, there is a phase transition at which the ferromagnetic order becomes unstable to a spin spiral. We model this transition, finding the exact location of the spin-spiral instability.
Fields of Study & Subjects
Physics of Superconductivity and Magnetism
Magnetic properties of thin films
Rare-earth and actinide compounds
Publication details
- Journal / source
- Physical review. B./Physical review. B
- Publisher
- American Physical Society (APS)
- Volume
- 113
- Issue
- 16
- Publication date
- 1 April 2026
- Language
- EN