Cu-Site Disorder in CuAl2O4 as Studied by XPS Spectroscopy

Abstract

The results of full study of X-ray photoelectron spectra (XPS) of spin-liquid candidate CuAl2O4 including the measurements of high-energy resolved core level (Cu $$2p$$, Al $$3p$$, O $$1s$$), Cu LMM Auger and valence band spectra are presented. The comparison of obtained results with spectra of reference samples and specially performed density functional theory calculations has confirmed a finite Cu site-disorder in CuAl2O4, where about 30% of Cu2+ ions occupy the octahedral sites. Obtained valence band spectra can be used in further theoretical studies aimed on the investigation of electronic and magnetic properties of this mysterious ma-terial.