Magnetic ground states of CrPS4 and NiPS3 monolayers from long-range exchange interactions
Abstract
We investigate the magnetic properties of monolayer CrPS4 and NiPS3 by combining first-principles calculations, second-principles spin models, and Monte Carlo simulations. Unlike conventional approaches that truncate exchange interactions after only a few shells and determine them by fitting total energies, we extract the magnetic exchange tensors directly from density functional theory using the LKAG formalism and include interactions until numerical convergence is achieved. We show that long-range exchange interactions qualitatively modify the magnetic behavior of both materials. In CrPS4, they destabilize the previously predicted ferromagnetic ground state and stabilize a spin-spiral phase, reducing the critical temperature to about 21\,K, in agreement with available experiments. The resulting magnetic phase diagram contains multiple collinear and non-collinear phases that can be tuned by temperature and external magnetic fields. In NiPS3, the experimentally observed zigzag antiferromagnetic order only emerges when exchange interactions up to the fifth shell are included. These results demonstrate that quantitatively predictive spin models for thiophosphate monolayers require long-range exchange interactions and provide a predictive framework for accurately describing two-dimensional van der Waals magnets.
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BibTeX
@misc{nagyfalusi2026magnetic,
title = {{Magnetic ground states of CrPS$_4$ and NiPS$_3$ monolayers from long-range exchange interactions}},
author = {Balazs Nagyfalusi and Ritesh Das and Alvaro Bermejillo-Seco and Herr S. J. van der Zant and Yaroslav M. Blanter and Amador Garcia-Fuente and Jaime Ferrer},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2607.20631},
eprint = {2607.20631},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.20631},
}
RIS
TY - UNPB
TI - Magnetic ground states of CrPS_4 and NiPS_3 monolayers from long-range exchange interactions
AU - Balazs Nagyfalusi
AU - Ritesh Das
AU - Alvaro Bermejillo-Seco
AU - Herr S. J. van der Zant
AU - Yaroslav M. Blanter
AU - Amador Garcia-Fuente
AU - Jaime Ferrer
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2607.20631
UR - https://arxiv.org/abs/2607.20631
AB - We investigate the magnetic properties of monolayer CrPS_4 and NiPS_3 by combining first-principles calculations, second-principles spin models, and Monte Carlo simulations. Unlike conventional approaches that truncate exchange interactions after only a few shells and determine them by fitting total energies, we extract the magnetic exchange tensors directly from density functional theory using the LKAG formalism and include interactions until numerical convergence is achieved. We show that long-range exchange interactions qualitatively modify the magnetic behavior of both materials. In CrPS_4, they destabilize the previously predicted ferromagnetic ground state and stabilize a spin-spiral phase, reducing the critical temperature to about 21\,K, in agreement with available experiments. The resulting magnetic phase diagram contains multiple collinear and non-collinear phases that can be tuned by temperature and external magnetic fields. In NiPS_3, the experimentally observed zigzag antiferromagnetic order only emerges when exchange interactions up to the fifth shell are included. These results demonstrate that quantitatively predictive spin models for thiophosphate monolayers require long-range exchange interactions and provide a predictive framework for accurately describing two-dimensional van der Waals magnets.
ER -