Figure 1.

XPEEM setup and exfoliated Fe₅GeTe₂ flake. (a) Experimental XPEEM setup and layered Fe₅GeTe₂ crystal structure on an Au underlayer. The sample was capped with an amorphous Se (a-Se) layer. (b) Optical micrograph showing exfoliated flake with trilayer (3L, marked by a dotted line), four-layer (4L), and bulk-like (nL) regions. The thicknesses have been cross-calibrated with atomic force microscopy (Figure S2) and via the intensity of the L₃ absorption peak. (c) Spatial XAS scan of an ultrathin mono- and bilayer area of the sample. The spatial integration of the XAS spectra over the three colored areas (see XPEEM image in inset) reveals metallic Fe L₃ and L₂ edges, indicating the absence of oxidation (see Figure S3 for the spectrum of oxidized Fe₅GeTe₂).