A prominent character of two-dimensional magnetic systems is the enhanced spin fluctuations, which however reduce the ordering temperature. Here we report that a magnetic field of only one-thousandth of the Heisenberg superexchange interaction can induce a crossover, which for practical purposes is the effective ordering transition, at temperatures about 6 times of the Neel transition in a site-diluted two-dimensional anisotropic quantum antiferromagnet. Such a strong magnetic response is enabled because the system directly enters the antiferromagnetically ordered state from the isotropic disordered state skipping the intermediate anisotropic stage. The underlying mechanism is achieved on a pseudospin-half square lattice realized in the [(SrIrO3)1/(SrTiO3)2] superlattice thin film that is designed to linearly couple the staggered magnetization to external magnetic fields by virtue of the rotational symmetry-preserving Dzyaloshinskii Moriya interaction. Our model analysis shows that the skipping of the anisotropic regime despite the finite anisotropy is due to the enhanced isotropic fluctuations under moderate dilution.
@article{arxiv.2311.18201,
title = {Extraordinary magnetic response of an anisotropic 2D antiferromagnet via site-dilution},
author = {Junyi Yang and Hidemaro Suwa and Derek. Meyers and Han Zhang and Lukas Horak and Zhan Zhang and Jenia Karapetrova and Jong-Woo Kim and Philip J. Ryan and Mark. P. M. Dean and Lin Hao and Jian Liu},
journal= {arXiv preprint arXiv:2311.18201},
year = {2023}
}