Eu triangular lattice layer compounds described by the general formula $\mathrm{Eu}{A}_2{X}_2$ have attracted growing attention due to a wide range of layered crystal structures and corresponding magnetic topological phases, arising from the coexistence of large Eu magnetic moments and energetically inverted $A$ and $X$ bands. Among the $\mathrm{Eu}{A}_2{X}_2$ family, ${\mathrm{EuIn}}_2{\mathrm{Sb}}_2$ has been predicted to host a robust axion insulator and higher-order topological insulator states by stronger spin-orbit coupling but still needs to be experimentally realized, including the structural identification. Here, we report the epitaxial stabilization of ${\mathrm{EuIn}}_2{\mathrm{Sb}}_2$ by adopting the molecular beam epitaxy technique. Structural characterization reveals that ${\mathrm{EuIn}}_2{\mathrm{Sb}}_2$ films are based on a unique In-on-In stacking, forming a different trilayer structure distinct from previously predicted structures in the $\mathrm{Eu}{A}_2{X}_2$ family. In addition to the in-plane antiferromagnetic ordering at $T_{\text{N}}=10.5\mathrm{K}$, the stronger spin-orbit coupling and enhanced In-In hybridization in ${\mathrm{EuIn}}_2{\mathrm{Sb}}_2$ make it an ideal candidate of axion insulator and higher-order topological insulator phases. These results establish ${\mathrm{EuIn}}_2{\mathrm{Sb}}_2$ as a member of the $\mathrm{Eu}{A}_2{X}_2$ family and offer an advanced platform for exploring these magnetic topological phases.

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• Rare-earth magnetic materials
• Thin films
• Topological materials