Abstract
Janus 2D materials, characterized by their mirror plane asymmetry, exhibit exceptional properties such as the Rashba effect, piezoelectricity, and photocatalysis, making them valuable in electronics, spintronics, and energy applications. While theoretical designs predict high thermoelectric and photocatalytic performance for Janus MXene, experimental synthesis remains unachieved due to challenges in fabricating symmetry-breaking MAX phase precursors. Existing MAX phases with in-plane or out-of-plane ordering retain inversion symmetry, making them unsuitable for Janus MXene synthesis. In this study, we report a class of chemically ordered MAX phase, (Ti3/11Zr2/11Hf3/11Ta3/11)3(Al2/3Sn1/3)C2, as a candidate precursor for Janus MXenes. We experimentally verified its unique asymmetric ordering through structural characterization. Further atomic-scale analysis via X-ray total scattering and reverse Monte Carlo (RMC) modeling reveals intricate chemical ordering and their possible correlation with atomic displacements. This work provides a pathway for synthesizing Janus MXenes and highlights the structural requirements for achieving symmetry-breaking in MAX phases.
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The present study was funded by the National Research Foundation of Korea (NRF), supported by the Korean government’s Ministry of Science and ICT (MSIT) (NRF-2021M2D2A1A02043946)
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Lee, M., Seong, H.W. & Ryu, H.J. An asymmetrically out-of-plane ordered MAX phase as a precursor for Janus MXenes. Nat Commun (2026). https://doi.org/10.1038/s41467-026-72561-y
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DOI: https://doi.org/10.1038/s41467-026-72561-y
