The recent discovery of two-dimensional (2D) magnetic materials has brought magnetism to the flatland. This has opened up exciting opportunities for the exploration of fundamental physics as well as for novel device applications. Here, we predict a new thermodynamically stable 2D magnetic material, K2CoS2, which retains its in-plane anti-ferromagnetic order down to the monolayer and bilayer limits. We find that the magnetic moments (2.5μB/Co) are aligned along the intra-Co chains, from monolayer to bulk. The non-magnetic electronic spectrum of both the monolayer and bilayer films is found to host flat bands and van-Hove singularities, which in instrumental in giving rise to the the magnetic ground state. Based on classical Monte-Carlo simulations, we estimate the Neel temperature for the antiferromagnetic monolayer to be ≈15K. Our study thus establishes that K2CoS2 hosts a robust antiferromagnetic state which persists from the monolayer limit to the bulk material.
@article{arxiv.2005.12868,
title = {K$_2$CoS$_2$: A new two-dimensional in-plane antiferromagnetic insulator},
author = {Anan Bari Sarkar and Barun Ghosh and Bahadur Singh and Somnath Bhowmick and Hsin Lin and Arun Bansil and Amit Agarwal},
journal= {arXiv preprint arXiv:2005.12868},
year = {2022}
}
Comments
final revised version; Phys. Rev. B 102, 035420 (2020)