Work

An asymmetrically out-of-plane ordered MAX phase as a precursor for Janus MXenes

Year: 2026

Type: article

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. Creating 2D Janus MXenes requires precursor MAX phases without mirror symmetry. This study synthesizes an asymmetric out-of-plane MAX phase as a promising precursor, verifying its structure via electron microscopy and Reverse Monte Carlo modelling.

Source: Nature Communications

DOI: 10.1038/s41467-026-72561-y

Authors: Minseok Lee, Hyun Woo Seong, Ho Jin Ryu

Institutions: Korea Atomic Energy Research Institute, Korea Advanced Institute of Science and Technology

Language: English

Topic: MXene and MAX Phase Materials

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $6,990

Funder: National Research Foundation of Korea