Cu-Site Disorder in CuAl2O4 as Studied by XPS Spectroscopy
Ivan S. Zhidkov, Alexei А. Belik, Andrey I. Kukharenko, S. O. Cholakh, Leonid S. Taran, A. Fujimori, S. V. Streltsov, E.Z. Kurmaev
Abstract
The results of full study of X-ray photoelectron spectra (XPS) of spin-liquid candidate CuAl 2 O 4 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 CuAl 2 O 4 , where about 30% of Cu 2+ 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.