Abstract
We present a detailed study of the ground-state phase diagram of the classical frustrated Heisenberg model on the face-centered-cubic lattice. By considering exchange interactions to third nearest neighbors, we find commensurate, helimagnetic, as well as noncollinear, multi-Q orders which include noncoplanar and chiral spin structures. We reveal the presence of subextensively degenerate manifolds that appear at triple points and certain phase boundaries in the phase diagram. Within these manifolds, the spin Hamiltonian can be recast as a complete square of spins on finite motifs, permitting us to identify families of exact ground-state spin configurations in real space—these include randomly stacked ferro- or antiferromagnetically ordered planes and interacting ferromagnetic chains, among others. Finally, we critically investigate the ramifications of our findings on the example of the Ising model, where we exactly enumerate all the states numerically for finite clusters.
3 More- Received 30 June 2020
- Revised 20 October 2020
- Accepted 28 October 2020
DOI:https://doi.org/10.1103/PhysRevResearch.2.043278
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society