10.48788/DVUA/DGS7UW Tkach, Vira0000-0002-2403-8607(Frantsevich Institute for Problems of Materials Science of NAS of Ukraine)O.Y. Khyzhun0000-0001-6727-643X(Frantsevich Institute for Problems of Materials Science of NAS of Ukraine)N.M. Denysyuk0000-0002-0492-1945(Frantsevich Institute for Problems of Materials Science of NAS of Ukraine)Luzhnyi Ivan Vasyliovych0000-0001-6727-643X(Frantsevich Institute for Problems of Materials Science of NAS of Ukraine)Kopylova Kateryna Ihorivna0000-0001-6796-390X(Frantsevich Institute for Problems of Materials Science of NAS of Ukraine) DataverseUA 2026 The electronic structure and surface chemical states of a Cu2HgGeSe4 single crystal, grown by the Bridgman–Stockbarger method, were investigated using X-ray photoelectron spectroscopy (XPS) for pristine and Ar+ ion-irradiated surfaces. High-resolution core-level XPS spectra (Cu 2p, Hg 4f, Ge 3d, Se 3d, Se 3p) and valence-band spectra were recorded before and after Ar+ ion sputtering to evaluate the core-level binding energies, chemical state preservation, and structural stability of the Cu2HgGeSe4 surface under ion-beam treatment. Tkach Vira Andriyvna(Frantsevich Institute for Problems of Materials Science of NAS of Ukraine)Frantsevych Institute for Problems of Materials Science of NAS of Ukraine(N.A.S. of Ukraine)