Phase-controlled growth of 2D crystals of the MB<sub>2</sub>T<sub>4</sub> family via a flux-assisted method.

Wang, Xingguo; Yang, Shiqi; Huang, Xinyue; Wei, Juntian; Jiang, Huaning; He, Qianqian; Si, Kunpeng; Li, Bixuan et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Van der Waals materials of the MB<sub>2</sub>T<sub>4</sub> family (M = transition metal or rare-earth metal, B = Bi or Sb, T = Te, Se, or S) have attracted wide interest for their exotic topological and magnetic properties, as well as potential spintronic applications. However, the direct growth of 2D ternary MB<sub>2</sub>T<sub>4</sub> remains challenging due to multiple competing phases and complex atomic arrangements. Here, we report a flux-assisted, phase-controlled growth strategy to directly grow six distinct 2D MB<sub>2</sub>T<sub>4</sub> crystals. Using MB<sub>2</sub>T<sub>4</sub> bulk powder as precursor, its dissolution into the cosolvent ensures stoichiometric control, while thermodynamic-kinetic equilibrium suppresses phase separation. Taking MnSb<sub>2</sub>Te<sub>4</sub> as an example, we obtained highly ordered septuple layers, with superconducting quantum interference device (SQUID) and reflective magnetic circular dichroism (RMCD) measurements confirming layer-dependent ferromagnetism and Curie temperature (T<sub>c</sub>) ranging from 12.3 to 33.7 K. This strategy provides an effective route for synthesizing complex layered crystals and offers versatile platforms for advancing spintronic applications.