Preferred Cleavage Plane and Surface Morphology of EuAl4(001) studied by Scanning Tunneling Microscopy, Low Energy Electron Diffraction, and Density Functional Theory

Centrally symmetric magnets capable of hosting skyrmions have been the focus of intense interest due to the lack of Dzyaloshinskii-Moriya interaction (DMI). Since inversion symmetry is preserved in centrosymmetric materials, a mechanism other than the DM interaction must be influencing the formation and stabilization of skyrmions in these materials. In addition, a mechanism of breaking inversion symmetry, such as charge density wave (CDW), has been discussed in these materials. The interplay between possible DMI, RKKY, and four-spin interactions in these materials provide a platform with rich possible magnetic texture phase diagrams. Centrosymmetric EuAl₄ is one example of these skyrmion magnets and is especially desirable due to the small size (3nm) of skyrmions reported. Direct visualization of these small magnetic skyrmions are highly desired. Experimentally, spin-polarized scanning tunneling microscopy (SPSTM) is ideal for studying skyrmion with sizes in this range. However, a description of the surface morphology, local electronic properties and the surface termination remains unidentified on cleaved EuAl4 surfaces. In this talk, the cleavage plane, surface morphology and corresponding dI/dV spectra on cleaved EuAl4(001) single crystal studied by STM, LEED and DFT calculation will be discussed.