${\mathrm{EuAl}}_4$, a centrosymmetric magnetic rare-earth transition-metal intermetallic compound, exhibits intriguing properties, such as topological states and topological magnetic textures (skyrmions). The surface termination and morphology of the cleaved surface are still not fully explored, leading to a challenging understanding of surface sensitive measurements. Here, the cleaved ${\mathrm{EuAl}}_4\left(001\right)$ surface is studied via scanning tunneling microscopy and spectroscopy (STM/S) and low-energy electron diffraction (LEED). Topographic images reveal a step-and-terrace morphology with terrace sizes ranging from a few nanometers to a few microns. The step heights are determined to be predominately one-half unit cell ($\sim 5.58\AA$). The terraces exhibit a surface morphology with a roughness of $\sim 1.50\AA$. This is believed to be caused by equivalent Eu-Al and Al-Eu cleavage planes due to the centrosymmetric crystal structure together with the energetic cleaving process that disrupts the surface topography. Spectroscopic measurements on the surface yielded three distinct types of spectra, primarily contributed by Al adatoms (type 1), Eu adatoms (type 2), and a combination of both (type 3), as elucidated with the help of density functional theory calculations. Our results show that the cleaved ${\mathrm{EuAl}}_4$ (${\mathrm{BaAl}}_4$ family) surface exhibits a higher level of disorder than ${\mathrm{ThCr}}_2{\mathrm{Si}}_2$-type compounds.

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• Local density of states
• Roughness
• Surface reconstruction
• Rare-earth magnetic materials
• Scanning tunneling microscopy