The current family of experimentally realized two-dimensional magnetic materials consist of 3d transition metals with very weak spin-orbit coupling. In contrast, we report a new platform in a chemically bonded and layered 4d oxide, with strong electron correlations and competing spin-orbit coupling. We synthesize ultra-thin sheets of SrRu2O6 using scalable liquid exfoliation. These exfoliated sheets are characterized by complementary experimental and theoretical techniques. The thickness of the nano-sheets varies between three to five monolayers, and within the first-principles calculations, we show that antiferromagnetism survives in these ultra-thin layers. Experimental data suggest that exfoliation occurs from the planes perpendicular to the c-axis as the intervening hexagonal Sr-lattice separates the two-dimensional magnetic honeycomb Ru-layers. The high-resolution transmission electron microscope images indicate that the average inter-atomic spacing between the Ru-layers is slightly reduced, which agrees with the present calculations. The signatures of rotational stacking of the nanosheets are also observed. Such new two-dimensional platform offers enormous possibilities to explore emergent properties that appear due to the interplay between magnetism, strong correlations and spin-orbit coupling. Moreover, these effects can be further tuned as a function of layer thickness.
@article{arxiv.1904.12326,
title = {Non-van der Waals honeycomb antiferromagnet SrRu$_2$O$_6$ down to a few layers},
author = {Suvidyakumar Homkar and Bharat Chand and Shatruhan Singh Rajput and Sandeep Gorantla and Tilak Das and Rohit Babar and Shivprasad Patil and Ruediger Klingeler and Sunil Nair and Mukul Kabir and Ashna Bajpai},
journal= {arXiv preprint arXiv:1904.12326},
year = {2020}
}